Support some, ok and err wrappers and untyped function inputs

Track the LScript changes since the grammar was first written:

- some, ok and err are reserved prefix operators and wrapper patterns;
  the old |.some/|.ok/|.err forms and postfix/prefix ! are rejected
- function literal inputs may omit their type annotation, and tuple
  components may omit theirs; an empty typed tuple pattern is now just
  the unit pattern
- migrate fixtures, corpus, queries, CST contract and Rust tests

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

queries/highlights.scm

@@ -6,15 +6,18 @@
   "continue"
   "distinct"
   "else"
+  "err"
   "for"
   "if"
   "in"
   "loop"
   "match"
   "not"
+  "ok"
   "or"
   "pub"
   "return"
+  "some"
   "use"
 ] @keyword
 
@@ -41,6 +44,6 @@
 [
   "=" "+=" "-=" "*=" "/=" "%=" "&=" "^=" "|="
   "==" "<" "<=" ">" ">="
-  "+" "-" "*" "/" "%" "&" "|" "^" "~" "!"
+  "+" "-" "*" "/" "%" "&" "|" "^" "~"
   "->" "=>" "|>" "..<" "..=" "@"
 ] @operator