The default keymap uses alt-enter for `SelectAllMatches` for `context:
BufferSearchBar`.

Jetbrains keymap uses alt-enter for `ToggleCodeActions` for `context:
Editor`.

When focusing on search bar, currently alt-enter does not perform
`SelectAllMatches`, whereas `ToggleCodeActions` is triggered instead,
because search bar's text input element has `context: Editor
mode=single_line`.

This PR restricts `ToggleCodeActions` to `Editor (full mode)` context to
allow `SelectAllMatches` to be triggered for alt-enter when the search
bar is active.

Release Notes:

- Fixed alt-enter with JetBrains keymap ignoring `search::SelectAllMatches` in certain contexts ([11840](https://github.com/zed-industries/zed/issues/11840))