Sync styx tree-sitter grammar from upstream (#141)

## Summary
- Updates grammar.js with improved sequence whitespace handling
(`_seq_ws` rule)
- Updates highlights.scm with better key/sequence highlighting
- Adds brackets.scm for bracket matching
- Adds indents.scm for indentation support

## Test plan
- CI should run grammar tests

Author: fasterthanlime

langs/group-maple/styx/def/grammar/grammar.js

@@ -119,7 +119,8 @@ module.exports = grammar({
         $.raw_scalar,
       ),
 
-    immediate_sequence: ($) => seq(token.immediate("("), repeat(seq($.expr, optional($._ws))), ")"),
+    immediate_sequence: ($) =>
+      seq(token.immediate("("), repeat($._seq_ws), repeat(seq($.expr, repeat($._seq_ws))), ")"),
     immediate_object: ($) => seq(token.immediate("{"), optional($._object_body), "}"),
     immediate_unit: ($) => $._immediate_unit_at,
 
@@ -153,7 +154,8 @@ module.exports = grammar({
     unit: ($) => $._unit_at,
 
     // Sequence: (expr expr ...)
-    sequence: ($) => seq("(", repeat(seq($.expr, optional($._ws))), ")"),
+    // Per spec, WS includes newlines inside sequences
+    sequence: ($) => seq("(", repeat($._seq_ws), repeat(seq($.expr, repeat($._seq_ws))), ")"),
 
     // Object: { entries }
     object: ($) => seq("{", optional($._object_body), "}"),
@@ -194,5 +196,7 @@ module.exports = grammar({
     // Whitespace helpers
     _ws: ($) => /[ \t]+/,
     _newline: ($) => /\r?\n/,
+    // Whitespace inside sequences (includes newlines and comments per spec)
+    _seq_ws: ($) => choice(/[ \t]+/, $._newline, $.line_comment),
   },
 });

langs/group-maple/styx/def/queries/brackets.scm

@@ -0,0 +1,4 @@
+; Bracket pairs for Styx
+
+("{" @open "}" @close)
+("(" @open ")" @close)

langs/group-maple/styx/def/queries/highlights.scm

@@ -17,18 +17,24 @@
 ; Unit value
 (unit) @constant.builtin
 
-; Tags - more specific than bare_scalar, so comes after
-(tag) @label
+; Tags - styled same as unit since @ is the tag sigil
+(tag) @constant.builtin
 
 ; Attributes - key in attribute syntax
+; Use @keyword or @punctuation.special to make > stand out
 (attribute
   key: (bare_scalar) @property
-  ">" @operator)
+  ">" @keyword)
 
-; Keys in entries - bare scalars in the key position (overrides @string above)
+; Keys in entries - any scalar in the key position (overrides @string above)
 (entry
   key: (expr
-    payload: (scalar (bare_scalar) @property)))
+    payload: (scalar (_) @property)))
+
+; Sequence items are values, not keys (must come AFTER entry key rule to override)
+(sequence
+  (expr
+    payload: (scalar (_) @string)))
 
 ; Punctuation
 "{" @punctuation.bracket

langs/group-maple/styx/def/queries/indents.scm

@@ -0,0 +1,9 @@
+; Indentation queries for Styx
+
+; Objects and sequences increase indent
+(object) @indent
+(sequence) @indent
+
+; Closing brackets decrease indent
+"}" @outdent
+")" @outdent