settings_ui: Get editor settings working (#37330)

Closes #ISSUE

This PR includes the necessary work to get `EditorSettings` showing up
in the settings UI. Including making the `path` field on
`SettingsUiItem`'s optional so that top level items such as
`EditorSettings` which have `Settings::KEY = None` (i.e. are treated
like `serde(flatten)`) have their paths computed correctly for JSON
reading/updating.

It includes the first examples of a pattern I expect to continue with
the `SettingsUi` work with respect to settings reorganization, that
being adding missing defaults, and adding explicit values (or aliases)
to settings which previously relied on `null` being a value for optional
fields.

Release Notes:

- N/A *or* Added/Fixed/Improved ...

crates/editor/src/editor_settings.rs

@@ -61,7 +61,9 @@ pub struct EditorSettings {
 }
 
 /// How to render LSP `textDocument/documentColor` colors in the editor.
-#[derive(Copy, Clone, Debug, Default, Serialize, Deserialize, PartialEq, Eq, JsonSchema)]
+#[derive(
+    Copy, Clone, Debug, Default, Serialize, Deserialize, PartialEq, Eq, JsonSchema, SettingsUi,
+)]
 #[serde(rename_all = "snake_case")]
 pub enum DocumentColorsRenderMode {
     /// Do not query and render document colors.
@@ -75,7 +77,7 @@ pub enum DocumentColorsRenderMode {
     Background,
 }
 
-#[derive(Copy, Clone, Debug, Serialize, Deserialize, PartialEq, Eq, JsonSchema)]
+#[derive(Copy, Clone, Debug, Serialize, Deserialize, PartialEq, Eq, JsonSchema, SettingsUi)]
 #[serde(rename_all = "snake_case")]
 pub enum CurrentLineHighlight {
     // Don't highlight the current line.
@@ -89,7 +91,7 @@ pub enum CurrentLineHighlight {
 }
 
 /// When to populate a new search's query based on the text under the cursor.
-#[derive(Copy, Clone, Debug, Serialize, Deserialize, PartialEq, Eq, JsonSchema)]
+#[derive(Copy, Clone, Debug, Serialize, Deserialize, PartialEq, Eq, JsonSchema, SettingsUi)]
 #[serde(rename_all = "snake_case")]
 pub enum SeedQuerySetting {
     /// Always populate the search query with the word under the cursor.
@@ -101,7 +103,9 @@ pub enum SeedQuerySetting {
 }
 
 /// What to do when multibuffer is double clicked in some of its excerpts (parts of singleton buffers).
-#[derive(Default, Copy, Clone, Debug, Serialize, Deserialize, PartialEq, Eq, JsonSchema)]
+#[derive(
+    Default, Copy, Clone, Debug, Serialize, Deserialize, PartialEq, Eq, JsonSchema, SettingsUi,
+)]
 #[serde(rename_all = "snake_case")]
 pub enum DoubleClickInMultibuffer {
     /// Behave as a regular buffer and select the whole word.
@@ -120,7 +124,9 @@ pub struct Jupyter {
     pub enabled: bool,
 }
 
-#[derive(Default, Copy, Clone, Debug, Serialize, Deserialize, PartialEq, Eq, JsonSchema)]
+#[derive(
+    Default, Copy, Clone, Debug, Serialize, Deserialize, PartialEq, Eq, JsonSchema, SettingsUi,
+)]
 #[serde(rename_all = "snake_case")]
 pub struct JupyterContent {
     /// Whether the Jupyter feature is enabled.
@@ -292,7 +298,9 @@ pub struct ScrollbarAxes {
 }
 
 /// Whether to allow drag and drop text selection in buffer.
-#[derive(Copy, Clone, Default, Debug, Serialize, Deserialize, JsonSchema, PartialEq, Eq)]
+#[derive(
+    Copy, Clone, Default, Debug, Serialize, Deserialize, JsonSchema, PartialEq, Eq, SettingsUi,
+)]
 pub struct DragAndDropSelection {
     /// When true, enables drag and drop text selection in buffer.
     ///
@@ -332,7 +340,7 @@ pub enum ScrollbarDiagnostics {
 /// The key to use for adding multiple cursors
 ///
 /// Default: alt
-#[derive(Copy, Clone, Debug, Serialize, Deserialize, JsonSchema, PartialEq, Eq)]
+#[derive(Copy, Clone, Debug, Serialize, Deserialize, JsonSchema, PartialEq, Eq, SettingsUi)]
 #[serde(rename_all = "snake_case")]
 pub enum MultiCursorModifier {
     Alt,
@@ -343,7 +351,7 @@ pub enum MultiCursorModifier {
 /// Whether the editor will scroll beyond the last line.
 ///
 /// Default: one_page
-#[derive(Copy, Clone, Debug, Serialize, Deserialize, JsonSchema, PartialEq, Eq)]
+#[derive(Copy, Clone, Debug, Serialize, Deserialize, JsonSchema, PartialEq, Eq, SettingsUi)]
 #[serde(rename_all = "snake_case")]
 pub enum ScrollBeyondLastLine {
     /// The editor will not scroll beyond the last line.
@@ -357,7 +365,9 @@ pub enum ScrollBeyondLastLine {
 }
 
 /// Default options for buffer and project search items.
-#[derive(Copy, Clone, Default, Debug, Serialize, Deserialize, JsonSchema, PartialEq, Eq)]
+#[derive(
+    Copy, Clone, Default, Debug, Serialize, Deserialize, JsonSchema, PartialEq, Eq, SettingsUi,
+)]
 pub struct SearchSettings {
     /// Whether to show the project search button in the status bar.
     #[serde(default = "default_true")]
@@ -373,7 +383,9 @@ pub struct SearchSettings {
 }
 
 /// What to do when go to definition yields no results.
-#[derive(Copy, Clone, Debug, Default, Serialize, Deserialize, PartialEq, Eq, JsonSchema)]
+#[derive(
+    Copy, Clone, Debug, Default, Serialize, Deserialize, PartialEq, Eq, JsonSchema, SettingsUi,
+)]
 #[serde(rename_all = "snake_case")]
 pub enum GoToDefinitionFallback {
     /// Disables the fallback.
@@ -386,7 +398,9 @@ pub enum GoToDefinitionFallback {
 /// Determines when the mouse cursor should be hidden in an editor or input box.
 ///
 /// Default: on_typing_and_movement
-#[derive(Copy, Clone, Debug, Default, Serialize, Deserialize, PartialEq, Eq, JsonSchema)]
+#[derive(
+    Copy, Clone, Debug, Default, Serialize, Deserialize, PartialEq, Eq, JsonSchema, SettingsUi,
+)]
 #[serde(rename_all = "snake_case")]
 pub enum HideMouseMode {
     /// Never hide the mouse cursor
@@ -401,7 +415,9 @@ pub enum HideMouseMode {
 /// Determines how snippets are sorted relative to other completion items.
 ///
 /// Default: inline
-#[derive(Copy, Clone, Debug, Default, Serialize, Deserialize, PartialEq, Eq, JsonSchema)]
+#[derive(
+    Copy, Clone, Debug, Default, Serialize, Deserialize, PartialEq, Eq, JsonSchema, SettingsUi,
+)]
 #[serde(rename_all = "snake_case")]
 pub enum SnippetSortOrder {
     /// Place snippets at the top of the completion list
@@ -416,6 +432,7 @@ pub enum SnippetSortOrder {
 }
 
 #[derive(Clone, Default, Serialize, Deserialize, JsonSchema, SettingsUi)]
+#[settings_ui(group = "Editor")]
 pub struct EditorSettingsContent {
     /// Whether the cursor blinks in the editor.
     ///
@@ -424,7 +441,7 @@ pub struct EditorSettingsContent {
     /// Cursor shape for the default editor.
     /// Can be "bar", "block", "underline", or "hollow".
     ///
-    /// Default: None
+    /// Default: bar
     pub cursor_shape: Option<CursorShape>,
     /// Determines when the mouse cursor should be hidden in an editor or input box.
     ///
@@ -601,7 +618,7 @@ pub struct EditorSettingsContent {
 }
 
 // Status bar related settings
-#[derive(Clone, Default, Serialize, Deserialize, JsonSchema, PartialEq, Eq)]
+#[derive(Clone, Default, Serialize, Deserialize, JsonSchema, PartialEq, Eq, SettingsUi)]
 pub struct StatusBarContent {
     /// Whether to display the active language button in the status bar.
     ///
@@ -614,7 +631,7 @@ pub struct StatusBarContent {
 }
 
 // Toolbar related settings
-#[derive(Clone, Default, Serialize, Deserialize, JsonSchema, PartialEq, Eq)]
+#[derive(Clone, Default, Serialize, Deserialize, JsonSchema, PartialEq, Eq, SettingsUi)]
 pub struct ToolbarContent {
     /// Whether to display breadcrumbs in the editor toolbar.
     ///
@@ -640,7 +657,9 @@ pub struct ToolbarContent {
 }
 
 /// Scrollbar related settings
-#[derive(Copy, Clone, Debug, Serialize, Deserialize, JsonSchema, PartialEq, Default)]
+#[derive(
+    Copy, Clone, Debug, Serialize, Deserialize, JsonSchema, PartialEq, Default, SettingsUi,
+)]
 pub struct ScrollbarContent {
     /// When to show the scrollbar in the editor.
     ///
@@ -675,7 +694,9 @@ pub struct ScrollbarContent {
 }
 
 /// Minimap related settings
-#[derive(Copy, Clone, Default, Debug, Serialize, Deserialize, JsonSchema, PartialEq)]
+#[derive(
+    Copy, Clone, Default, Debug, Serialize, Deserialize, JsonSchema, PartialEq, SettingsUi,
+)]
 pub struct MinimapContent {
     /// When to show the minimap in the editor.
     ///
@@ -723,7 +744,9 @@ pub struct ScrollbarAxesContent {
 }
 
 /// Gutter related settings
-#[derive(Copy, Clone, Debug, Default, Serialize, Deserialize, JsonSchema, PartialEq, Eq)]
+#[derive(
+    Copy, Clone, Debug, Default, Serialize, Deserialize, JsonSchema, PartialEq, Eq, SettingsUi,
+)]
 pub struct GutterContent {
     /// Whether to show line numbers in the gutter.
     ///