Support relative line number on wrapped lines (#39268)

**Problem:** Current relative line numbering creates a mismatch with
vim-style navigation when soft wrap is enabled. Users must mentally
calculate whether target lines are wrapped segments or logical lines,
making `<n>j/k` navigation unreliable and cognitively demanding.

**How things work today:**
- Real line navigation (`j/k` moves by logical lines): Requires
determining if visible lines are wrapped segments before jumping. Can't
jump to wrapped lines directly.
- Display line navigation (`j/k` moves by display rows): Line numbers
don't correspond to actual row distances for multi-line jumps.

**Proposed solution:** Count and number each display line (including
wrapped segments) for relative numbering. This creates direct
visual-to-navigational correspondence where the relative number shown
always matches the `<n>j/k` distance needed.

**Benefits:**
- Eliminates mental overhead of distinguishing wrapped vs. logical lines
- Makes relative line numbers consistently actionable regardless of wrap
state
- Preserves intuitive "what you see is what you navigate" principle
- Maintains vim workflow efficiency in narrow window scenarios

Also explained an discussed in
https://github.com/zed-industries/zed/discussions/25733.

Release Notes:

Release Notes:

- Added support for counting wrapped lines as relative lines and for
displaying line numbers for wrapped segments. Changes
`relative_line_numbers` from a boolean to an enum: `enabled`,
`disabled`, or `wrapped`.

---------

Co-authored-by: Conrad Irwin <conrad.irwin@gmail.com>

crates/settings_ui/src/page_data.rs

@@ -1503,7 +1503,7 @@ pub(crate) fn settings_data(cx: &App) -> Vec<SettingsPage> {
                     }),
                     SettingsPageItem::SettingItem(SettingItem {
                         title: "Relative Line Numbers",
-                        description: "Whether the line numbers in the editor's gutter are relative or not.",
+                        description: "Controls line number display in the editor's gutter. \"disabled\" shows absolute line numbers, \"enabled\" shows relative line numbers for each absolute line, and \"wrapped\" shows relative line numbers for every line, absolute or wrapped.",
                         field: Box::new(SettingField {
                             json_path: Some("relative_line_numbers"),
                             pick: |settings_content| {

crates/settings_ui/src/settings_ui.rs

@@ -491,6 +491,7 @@ fn init_renderers(cx: &mut App) {
         .add_basic_renderer::<settings::IncludeIgnoredContent>(render_dropdown)
         .add_basic_renderer::<settings::ShowIndentGuides>(render_dropdown)
         .add_basic_renderer::<settings::ShellDiscriminants>(render_dropdown)
+        .add_basic_renderer::<settings::RelativeLineNumbers>(render_dropdown)
         // please semicolon stay on next line
         ;
 }