Editor tab bar settings (#7356)

This PR is another step to tabless editing (#6424, #4963). It adds
support for tab bar settings that allow the user to change its placement
or to hide completely.

Configuraton:

```json
"tab_bar": {
  "show": true
}
```

Placemnet options are "top", "bottom" and "no".

This PR intentionally doesn't affect tab bars of other panes (Terminal
for instance) to keep code changes small. I guess we'll do the rest in
separate PRs.

Release Notes:

- Added support for configuring the editor tab bar (part of #6424,
#4963).

---------

Co-authored-by: Mikayla <mikayla@zed.dev>

docs/src/configuring-zed.md

@@ -315,6 +315,82 @@ List of `string` values
 
 `boolean` values
 
+## Editor Tab Bar
+
+- Description: Settings related to the editor's tab bar.
+- Settings: `tab_bar`
+- Default:
+
+```json
+"tab_bar": {
+  "show": true,
+  "show_nav_history_buttons": true
+}
+```
+
+### Show
+
+- Description: Whether or not to show the tab bar in the editor.
+- Setting: `show`
+- Default: `true`
+
+**Options**
+
+`boolean` values
+
+### Navigation History Buttons
+
+- Description: Whether or not to show the navigation history buttons.
+- Setting: `show_nav_history_buttons`
+- Default: `true`
+
+**Options**
+
+`boolean` values
+
+## Editor Tabs
+
+- Description: Configuration for the editor tabs.
+- Setting: `tabs`
+- Default:
+
+```json
+"tabs": {
+  "close_position": "right",
+  "git_status": false
+},
+```
+
+### Close Position
+
+- Description: Where to display close button within a tab.
+- Setting: `close_position`
+- Default: `right`
+
+**Options**
+
+1. Display the close button on the right:
+
+```json
+{
+  "close_position": "right"
+}
+```
+
+2. Display the close button on the left:
+
+```json
+{
+  "close_position": "left"
+}
+```
+
+### Git Status
+
+- Description: Whether or not to show Git file status in tab.
+- Setting: `git_status`
+- Default: `false`
+
 ## Editor Toolbar
 
 - Description: Whether or not to show various elements in the editor toolbar.