LibCpp: Add function for retrieving TODO comments from the parser

Now `get_todo_entries` collects all TODO found within a comment
statement.

Userland/Libraries/LibCpp/Parser.cpp

@@ -961,6 +961,19 @@ void Parser::print_tokens() const
     }
 }
 
+Vector<String> Parser::get_todo_entries() const
+{
+    Vector<String> ret;
+    for (auto& token : m_tokens) {
+        if (token.type() == Token::Type::Comment) {
+            if (token.text().contains("TODO")) {
+                ret.append(token.text());
+            }
+        }
+    }
+    return ret;
+}
+
 NonnullRefPtr<StringLiteral> Parser::parse_string_literal(ASTNode& parent)
 {
     ScopeLogger<CPP_DEBUG> logger;

Userland/Libraries/LibCpp/Parser.h

@@ -35,6 +35,7 @@ public:
     void print_tokens() const;
     const Vector<String>& errors() const { return m_state.errors; }
     const Preprocessor::Definitions& preprocessor_definitions() const { return m_preprocessor_definitions; }
+    Vector<String> get_todo_entries() const;
 
     struct TokenAndPreprocessorDefinition {
         Token token;