docs: Add note about conflicting global macOS shortcut (#45186)

This is already noted in our `default-macos.json`, but was never
surfaced in our docs for some reason. A user noted their LSP completions
were not working because they were not aware of the conflicting global
shortcut.

Ref:
https://github.com/zed-industries/zed/issues/44970#issuecomment-3664118523

Release Notes:

- N/A
184001b33bKunall Banerjee committed on 12/18/2025, 2:13:59 AM· committed by GitHubparent225a2a8
1 file changedLine totals unavailable