docs: Add `"dock"` to `"terminal"` section (#16122)

Neil created 

Documentation-related fix for #16121.

Co-authored-by: Neil Alexander <neilalexander@users.noreply.github.com>

Release Notes:
* N/A

Change summary

docs/src/configuring-zed.md | 11 +++++++++++
1 file changed, 11 insertions(+)

Detailed changes

docs/src/configuring-zed.md 🔗 

@@ -1259,6 +1259,7 @@ List of `integer` column numbers
     "alternate_scroll": "off",
     "blinking": "terminal_controlled",
     "copy_on_select": false,
+    "dock": "bottom",
     "env": {},
     "font_family": null,
     "font_features": null,
@@ -1274,6 +1275,16 @@ List of `integer` column numbers
 }
 ```
 
+### Terminal: Dock
+
+- Description: Control the position of the dock
+- Setting: `dock`
+- Default: `bottom`
+
+**Options**
+
+`"bottom"`, `"left"` or `"right"`
+
 ### Terminal: Alternate Scroll
 
 - Description: Set whether Alternate Scroll mode (DECSET code: `?1007`) is active by default. Alternate Scroll mode converts mouse scroll events into up / down key presses when in the alternate screen (e.g. when running applications like vim or less). The terminal can still set and unset this mode with ANSI escape codes.