works similar to 'grep_lgrep' action toggling between the fuzzy
matching on the entire workspace symbols and live query which
sends a new LSP query with each keystroke, fuzzy query is saved
between toggles so it can be used as an extra filter for example:
live query 'foo', press ctrl-g and enter '!.lua', to exclude all
lua files.
Addittional changes:
- diagnostics decoupled from LSP, new options under 'diagnostics'
- symbols options has their own category under 'lsp.symbols'
- 'lsp_document_diagnostics' -> 'diagnostics_document'
- 'lsp_workspace_diagnostics' -> 'diagnostics_workspace'
- backward compatibility maintained for the above changes
- all symbols providers use 'async=true' by default
bhagwan