editor: Refactor EditorMode::Full (#28546)

This PR lightly refactors the `EditorMode::Full` exposing two new
methods: `is_full` and `set_mode`.

Motivation is to expose fields that modify the behavior when the editor
is in `Full` mode. By using is `mode.is_full()` instead of
`EditorMode::Full` we can introduce new fields without breaking other
places in the code.

Release Notes:

- N/A

Co-authored-by: Bennet Bo Fenner <bennetbo@gmx.de>

crates/editor/src/test.rs

@@ -108,7 +108,7 @@ pub(crate) fn build_editor(
     window: &mut Window,
     cx: &mut Context<Editor>,
 ) -> Editor {
-    Editor::new(EditorMode::Full, buffer, None, window, cx)
+    Editor::new(EditorMode::full(), buffer, None, window, cx)
 }
 
 pub(crate) fn build_editor_with_project(
@@ -117,5 +117,5 @@ pub(crate) fn build_editor_with_project(
     window: &mut Window,
     cx: &mut Context<Editor>,
 ) -> Editor {
-    Editor::new(EditorMode::Full, buffer, Some(project), window, cx)
+    Editor::new(EditorMode::full(), buffer, Some(project), window, cx)
 }