fix: preserve comment nodes at statement boundaries

The scanner previously folded comments into the terminator token, which
removed line_comment/block_comment nodes from the tree and broke
comment-based lint rules (TODO detection missed TODOs in script
sections). Now the scanner returns false when a comment follows the
newline run, so the comment is lexed as an ordinary extra and the
terminator is emitted after it — one terminator between statements, and
the comment survives as a node.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XaTroL9k3feq3MTAptE9bD

Author: edmundmiller

grammar.js

@@ -198,7 +198,7 @@ module.exports = grammar({
         $.output_declaration,
         $.when_declaration
       )),
-      repeat($.script_declaration),
+      repeat(seq($.script_declaration, optional($._terminator))),
       '}'
     ),
 
@@ -296,8 +296,7 @@ module.exports = grammar({
       optional($._terminator),
       repeat(seq($.script_statement, $._terminator)),  // Groovy prelude, each terminated
       // exec: sections are Groovy-only; script/shell/stub end in a string.
-      optional($.script_content),
-      optional($._terminator)
+      optional($.script_content)
     )),
 
     // Groovy statements allowed before the script string.