Eglot rename, create, delete support

["Lina Bhaile" <emacs-devel@linabee.uk>]

(Resending due to wrong From:)

Hi all,

The Language Server Protocol spec allows for servers to send requests to the
client (in this case Emacs/Eglot) to create, rename or delete files in the
project if the client advertises that it can do “resourceOperations”
[https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#resourceChanges].
Unfortunately Eglot does not support this in either HEAD or in Emacs 29. It’s
particularly useful for Java since the compiler for that language refuses to
compile a file if the name of a type does not match the file name, as well as
code actions for moving types from one package (namespace) to another.

I have a patch that adds support for rename requests to Eglot inside an
extension package for connecting to a Java language server, but it is very
hacky because it needs to advise eglot--apply-workspace-edit which will
mishandle parsing if it encounters an object with a different type than
TextDocumentEdit inside a workspace edit response
[https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#workspaceEdit].
Really, though, this code should be inside Eglot itself. I would share it on
the list but I do not have my copyright assigned yet, it's pushing around 125
lines with just rename support. As well I would like some review and to write
some tests as these are potentially destructive operations and I would like to
handle all the potential corner cases that might arise.

If someone could send me the copyright assignment forms that would be grand.

   	   Lina