Closes https://github.com/zed-industries/zed/issues/37144

Adjusts `editor::DeleteToPreviousWordStart`,
`editor::DeleteToNextWordEnd`, `editor::DeleteToNextSubwordEnd` and
`editor::DeleteToPreviousSubwordStart` actions to

* take whitespace sequences with length >= 2 into account and stop after
removing them (whilst movement would also include the word after such
sequences)

* take current language's brackets into account and stop after removing
the text before them

The latter is configurable and can be disabled with `"ignore_brackets":
true` parameter in the action.

Release Notes:

- Improved word deletions to consider whitespace sequences and brackets
by default