[NFC] Simplify lexer and move to header

src/parser/CMakeLists.txt

@@ -2,7 +2,6 @@ FILE(GLOB parser_HEADERS *.h)
 set(parser_SOURCES
  context-decls.cpp
  context-defs.cpp
- lexer.cpp
  parse-1-decls.cpp
  parse-2-typedefs.cpp
  parse-3-implicit-types.cpp

src/parser/contexts.h

@@ -1985,7 +1985,7 @@ struct ParseDefsCtx : TypeParserCtx<ParseDefsCtx>, AnnotationParserCtx {
   void setSrcLoc(const std::vector<Annotation>& annotations) {
     const Annotation* annotation = nullptr;
     for (auto& a : annotations) {
-      if (a.kind == srcAnnotationKind) {
+      if (a.kind.str == std::string_view("src")) {
         annotation = &a;
       }
     }