BREAKING-CHANGE: `command!` drops support to resolve unnecessary quote on callback

BREAKING-CHANGE: `map!` no longer resolves quoted callback in itself.
BREAKING-CHANGE: `map!` no longer accept special options `<command>`, `ex`, `<callback>`, and `cb`.
BREAKING-CHANGE: `map!` no longer interpret callback of which the first symbol matches `^<.+>` as Lua function, but as Ex command.
BREAKING-CHANGE: `map!` interprets callback in list as Lua function unless either symbol `&vim` precedes it or the first symbol of the list matches pattern `^<.+>`.

BREAKING-CHANGE: `augroup!` & `autocmd!`/`au!` no longer resolves quoted callback in itself.
BREAKING-CHANGE: `augroup!` & `autocmd!`/`au!` no longer accept special options `<command>`, `ex`, `<callback>`, and `cb`.
BREAKING-CHANGE: `augroup!` & `autocmd!`/`au!` no longer interpret callback of which the first symbol matches `^<.+>` as Lua function, but as key sequence.
BREAKING-CHANGE: `augroup!` & `autocmd!`/`au!` interprets callback in list as Lua function unless either symbol `&vim` precedes it or the first symbol of the list matches pattern `^<.+>`.

BREAKING-CHANGE: remove deprecated `map!` wrapper macros: `nmap!`, `vmap!`, ...
BREAKING-CHANGE: remove deprecated macro `augroup+`; use `augroup!` with `{:clear false}` instead.