Add `.swift-format` to the repo and format the repo with `swift-format`.
This commit does not add any automation to enforce formatting of sourcekit-lsp in CI. The goal of this commit is to get the majority of source changes out of the way so that the diff of actually enforcing formatting will have fewer changes or conflicts.
* Send `didSave` notifications to clangd if it supports it
- Minor update to the LSP protocol for `didSave` and `colorProvider` to be more in line with the spec
- Only send color requests over to clangd if it supports it
Rationale for this change: clangd recently implemented didSave support,
it is used to rebuild preambles when the user edits a header file
referenced by an open file.
Change-Id: Ie6e2198bdeccb9d1b4083806c254475baadc2d2b
Request types should always have the suffix Request and notifications
should end with Notification.
Also moved all request and notification types into separate folders to
reduce the number of files in the LanguageServerProtocol folder.
