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/editor/src/editor_settings.rs

@@ -3,12 +3,12 @@ use core::num;
 use gpui::App;
 use language::CursorShape;
 use project::project_settings::DiagnosticSeverity;
-use settings::Settings;
 pub use settings::{
     CurrentLineHighlight, DelayMs, DisplayIn, DocumentColorsRenderMode, DoubleClickInMultibuffer,
     GoToDefinitionFallback, HideMouseMode, MinimapThumb, MinimapThumbBorder, MultiCursorModifier,
     ScrollBeyondLastLine, ScrollbarDiagnostics, SeedQuerySetting, ShowMinimap, SnippetSortOrder,
 };
+use settings::{RelativeLineNumbers, Settings};
 use ui::scrollbars::{ScrollbarVisibility, ShowScrollbar};
 
 /// Imports from the VSCode settings at
@@ -33,7 +33,7 @@ pub struct EditorSettings {
     pub horizontal_scroll_margin: f32,
     pub scroll_sensitivity: f32,
     pub fast_scroll_sensitivity: f32,
-    pub relative_line_numbers: bool,
+    pub relative_line_numbers: RelativeLineNumbers,
     pub seed_search_query_from_cursor: SeedQuerySetting,
     pub use_smartcase_search: bool,
     pub multi_cursor_modifier: MultiCursorModifier,