Document hidden_files setting (#64403)

## Objective

While suggesting #64399, I realized `hidden_files` didn’t have an entry
in the settings reference. This PR fills that gap.

## Testing

Checked the descriptions against the implementation and existing tests.

## Self-Review Checklist:

- [x] I’ve reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content adheres to Zed’s UI standards
([UX/UI](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
and
[icon](https://github.com/zed-industries/zed/blob/main/crates/icons/README.md)
guidelines)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

---

Release Notes:

- N/A

docs/src/project-panel.md

@@ -162,8 +162,7 @@ See also [Diagnostics & Quick Fixes](./diagnostics.md) for editor and tab diagno
 
 - `project_panel.hide_gitignore` hides files matched by `.gitignore`. Toggle
   this with {#action project_panel::ToggleHideGitIgnore}.
-- `project_panel.hide_hidden` hides dotfiles and other hidden entries. Toggle
-  with {#action project_panel::ToggleHideHidden}.
+- `project_panel.hide_hidden` hides entries matching [`hidden_files`](./reference/all-settings.md#hidden-files) (dotfiles and dotfolders by default). Toggle with {#action project_panel::ToggleHideHidden}.
 
 ### Sorting
 

docs/src/reference/all-settings.md

@@ -2930,6 +2930,31 @@ Example:
 
 `boolean` values
 
+## Hidden Files {#hidden-files}
+
+- Description: Glob patterns that mark files and folders as hidden in the Project Panel.
+- Setting: `hidden_files`
+- Default: `["**/.*"]`
+
+**Options**
+
+List of `string` glob patterns.
+
+The default matches files and folders whose names start with a dot. Files inside matching folders are also considered hidden.
+
+The [Project Panel](../project-panel.md#hiding-files) shows hidden entries by default. To hide them, enable **Hide Hidden** under **Panels > Project Panel** in the Settings Editor, or set `project_panel.hide_hidden` to `true`.
+
+Customizing `hidden_files` replaces the default patterns. To hide `*.log` files while keeping dotfiles and dotfolders hidden, add this to your `settings.json`:
+
+```json [settings]
+{
+  "hidden_files": ["**/*.log", "**/.*"],
+  "project_panel": {
+    "hide_hidden": true
+  }
+}
+```
+
 ## Indent Guides
 
 - Description: Configuration related to indent guides. Indent guides can be configured separately for each language.