Named arguments in commands + many grammar fixes (#20994)

* Breaking parser changes, implement https://github.com/nim-lang/RFCs/issues/442

Types are separated from expressions and better reflected in the grammar.

* add test

* more accurate grammar

* fix keyword typedescs

* accept expressions in proc argument lists

* CI "fixes"

* fixes

* allow full ref expressions again, adapt old tests

* cleanup, fix some tests

* improve grammar, try and revert semtypes change

* restrict sigil binding to identOrLiteral

* fix, should have caught this immediately

* add changelog entry, fix double not nil bug

* correct grammar

* change section

* fix

* real fix hopefully

* fix test

* support LL(1) for tuples

* make grammar.txt too

tests/effects/teffects1.nim

@@ -17,7 +17,7 @@ proc forw: int {. .}
 proc lier(): int {.raises: [IO2Error].} = #[tt.Hint
                             ^ 'lier' cannot raise 'IO2Error' [XCannotRaiseY] ]#
   writeLine stdout, "arg" #[tt.Error
-            ^ writeLine stdout, ["arg"] can raise an unlisted exception: ref IOError ]#
+  ^ writeLine stdout, ["arg"] can raise an unlisted exception: ref IOError ]#
 
 proc forw: int =
   raise newException(IOError, "arg")