X-CC-Debbugs: João Távora <joaotavora@gmail.com>

I'd like to propose adding an option that makes server modifications by
Eglot less invasive.  The current behaviour is to make the changes
directly in a buffer and open the remaining files to make the
modifications in those as well (?).  If `eglot-use-diffs' is enabled,
all confirmations are prepared as patches in a pop-up buffer that the
user can review and apply at will.  To my knowledge there is no general
`diff-apply-hunk' that will apply all the changes from a buffer, but
that is a separate issue that can be fixed in a separate patch.

(Note, I'm still testing emacs-29, so the patch was developed on that
branch.  But it should be applied to master)