editor: Highlight all matching occurrences of text in selection (#24835)

Closes #12635

- [x] Get it working
- [x] Disable for multi cursor
- [x] Disable for vim visual line selection
- [x] Add setting to disable it
- [x] Add scrollbar marker
- [x] Handle delete state capturing selection

Preview:

https://github.com/user-attachments/assets/a76cde64-4f6c-4575-91cc-3a03a954e7a9

Release Notes:

- Added support to highlight all matching occurrences of text within the
selection in editor.

---------

Co-authored-by: Agus Zubiaga <agus@zed.dev>
Co-authored-by: Danilo <danilo@zed.dev>

docs/src/configuring-zed.md

@@ -472,6 +472,19 @@ List of `string` values
 "current_line_highlight": "all"
 ```
 
+## Selection Highlight
+
+- Description: Whether to highlight all occurrences of the selected text in an editor.
+- Setting: `selection_highlight`
+- Default: `true`
+
+## Selection Highlight Debounce
+
+- Description: The debounce delay before querying highlights based on the selected text.
+
+- Setting: `selection_highlight_debounce`
+- Default: `75`
+
 ## LSP Highlight Debounce
 
 - Description: The debounce delay before querying highlights from the language server based on the current cursor location.
@@ -532,6 +545,7 @@ List of `string` values
   "cursors": true,
   "git_diff": true,
   "search_results": true,
+  "selected_text": true,
   "selected_symbol": true,
   "diagnostics": "all",
   "axes": {
@@ -611,6 +625,16 @@ List of `string` values
 
 `boolean` values
 
+### Selected Text Indicators
+
+- Description: Whether to show selected text occurrences in the scrollbar.
+- Setting: `selected_text`
+- Default: `true`
+
+**Options**
+
+`boolean` values
+
 ### Selected Symbols Indicators
 
 - Description: Whether to show selected symbol occurrences in the scrollbar.