Add a language server for carbon as part of GSoC.
This currently does code outline using toolchain parser.
See development steps in utils/vscode/README.md for running and using
language server.
Updates the dependencies flex and bison to latest. @jonmeow suggested in the Discord the patched versions should hopefully go away now, and so those are removed as well.
This resolves an issue I was seeing where none of the `lit` based test
executions could import the `lit` module. The `imports` attribute this
adds seems like the essential part, but I added both while there.
I'm not sure if this is the right fix though as no one else seems to
have been having trouble and worried this is actually something weird
with my setup that is broken. Ideas or suggestions welcome!
Per #2463 we're looking at adding more patches, this updates .pre-commit-config.yaml and sets up the directory structure to be more accommodating to more patches.
maan2003
psh
Chandler Carruth
micttyl
Jon Ross-Perkins