Using codespell 2.2-dev from current git.
Added `misc/scripts/codespell.sh` to make it easier to run it once in a
while and update the skip and ignore lists.
For the time being we don't support writing a description for those, preferring
having all details in the method's description.
Using self-closing tags saves half the lines, and prevents contributors from
thinking that they should write the argument or return documentation there.
Changes:
* EngineDebugger is exposed to gdscript. Game side of communication can be implemented through it.
* EditorDebuggerPlugin is added which handles the editor side of communication.
