Add support for textDocument/onTypeFormatting and then integrate that for specific IDE keystrokes to provide a better text editor experience

[SCWells72]

The textDocument/onTypeFormatting language feature could be used to provide a better as-you-type code formatting experience for languages integrated into JetBrains IDEs exclusively via LSP. As long as it's quick enough for a true interactive experience, it would make sense to trigger it (optionally based on end user config) on Enter, Backspace, open/close brace/bracket/paren/etc., and potentially other keys.