fix(semantic_tokens): highlight braced stored-proc names in lappend

Treat braced lappend arguments that match custom or standard procedure names as
function tokens for semantic highlighting. This applies the same visual
highlighting as calls but does not treat the literal as executable Tcl. Previously
such braced stored-proc names were not highlighted.

server/src/tools/semantic_tokens.py

@@ -4,7 +4,7 @@ from typing import List
 import attrs
 from common.load_data import standard_items
 from tclint.commands.plugins import PluginManager
-from tclint.syntax_tree import BareWord, Command, QuotedWord, Visitor
+from tclint.syntax_tree import BareWord, BracedWord, Command, QuotedWord, Visitor
 from tools.variable_names import variable_name
 from tools.tcloo_symbols import class_symbols
 from tools.tcloo_completion import _analyze
@@ -173,6 +173,15 @@ class _Highlighter(Visitor):
     def visit_command(self, command: Command):
         routine = command.routine
 
+        # Stored procedure names in braced lappend arguments use the same
+        # highlighting as calls, without treating the literal as executable Tcl.
+        if routine.contents in {"lappend", "::lappend"}:
+            for argument in command.args:
+                if (isinstance(argument, BracedWord)
+                        and argument.contents in self._custom_function_names | _STANDARD_PROC_NAMES):
+                    line, col = argument.contents_pos
+                    self._append_token((line - 1, col - 1), len(argument.contents), "function", [])
+
         # Highlight functions (custom or standard) when used as the routine
         name = getattr(routine, "contents", None)
         if name: