[tree-sitter] More C++ fixes

Built a new `tree-sitter-cpp` parser from latest master to fix a parsing error with variable assignment. Also added/tweaked scopes for some specific scenarios.

packages/language-c/grammars/modern-tree-sitter-c.cson

@@ -17,3 +17,6 @@ fileTypes: [
   'c'
   'h.in'
 ]
+
+comments:
+  start: '// '

packages/language-c/grammars/modern-tree-sitter-cpp.cson

@@ -6,6 +6,7 @@ parser: 'tree-sitter-cpp'
 injectionRegex: '^(c|C)(\\+\\+|pp|PP)$'
 
 treeSitter:
+  parserSource: 'github:tree-sitter/tree-sitter-cpp#a90f170f92d5d70e7c2d4183c146e61ba5f3a457'
   grammar: 'tree-sitter-cpp/tree-sitter-cpp.wasm'
   highlightsQuery: 'tree-sitter-cpp/highlights.scm'
   tagsQuery: 'tree-sitter-cpp/tags.scm'
@@ -33,3 +34,6 @@ fileTypes: [
 ]
 
 contentRegex: '\n\\s*(namespace|class|template)\\s+'
+
+comments:
+  start: '// '

packages/language-c/grammars/tree-sitter-cpp/highlights.scm

@@ -51,12 +51,14 @@
 
 (primitive_type) @support.type.builtin.cpp
 
-; Type parameters
-(template_argument_list
-  (type_descriptor
-    type: (type_identifier) @variable.parameter.type.cpp
-    (#set! capture.final true)))
+; Mark all function definition types with data…
+(function_definition
+  type: (_) @_IGNORE_
+  (#set! functionDefinitionType true))
 
+; …so that we can detect when a type identifier is part of a template/generic.
+((type_identifier) @variable.parameter.type.cpp
+  (#is? test.descendantOfNodeWithData functionDefinitionType))
 
 (class_specifier
   (type_identifier) @entity.name.class.cpp
@@ -150,6 +152,13 @@
     name: (identifier) @support.other.function.cpp)
   (#set! capture.final true))
 
+; The "foo" in `troz::foo<SomeType>(...)`.
+(call_expression
+  function: (qualified_identifier
+    name: (template_function
+      name: (identifier) @support.other.function.cpp))
+  (#set! capture.final true))
+
 (call_expression
   (identifier) @support.other.function.cpp
   (#set! capture.final true))
@@ -272,7 +281,6 @@
   (null)
   (true)
   (false)
-  (nullptr)
 ] @constant.language._TYPE_.cpp
 
 ((identifier) @constant.cpp