`lsp-deferred` calls `lsp` and `lsp` seems to do something expensive
whether or not lsp-mode is already active. Over TRAMP, this is much too
expensive, so we no-op lsp-deferred if lsp-mode is already active.
- Update README
- Add eglot-specifics to cc, rs, py, hs
removing unused lsp-mode packages when eglot is active
- Add eglot-specific bindings
- Add doctor warnings for debugger +lsp and +peek
- Add eglot-backed lookup-handlers
- Add flycheck checker using eglot for :checkers
syntax users (using flycheck/flycheck#1676 and
flycheck/flycheck#1592 discussion).
This implementation is based on @marsam code, and uses recent
Flycheck development in order to make the code smaller and
easier to maintain.
