LanguageServers/Cpp: Complete Preprocessor definitions

Preprocessor definitions now appear in the AutoComplete suggestions box
as well as in the Locator.

Userland/Libraries/LibCpp/Preprocessor.cpp

@@ -105,10 +105,14 @@ void Preprocessor::handle_preprocessor_line(const StringView& line)
         if (m_state == State::Normal) {
             auto key = lexer.consume_until(' ');
             consume_whitespace();
+
             DefinedValue value;
+            value.line = m_line_index;
+
             auto string_value = lexer.consume_all();
             if (!string_value.is_empty())
                 value.value = string_value;
+
             m_definitions.set(key, value);
         }
         return;

Userland/Libraries/LibCpp/Preprocessor.h

@@ -43,6 +43,8 @@ public:
 
     struct DefinedValue {
         Optional<StringView> value;
+        size_t line {0};
+        size_t column {0};
     };
     using Definitions = HashMap<StringView, DefinedValue>;
 

Userland/Libraries/LibGUI/AutocompleteProvider.h

@@ -42,6 +42,7 @@ public:
 
     enum class CompletionKind {
         Identifier,
+        PreprocessorDefinition,
     };
 
     enum class Language {
@@ -66,7 +67,8 @@ public:
         Function,
         Struct,
         Class,
-        Variable
+        Variable,
+        PreprocessorDefinition,
     };
 
     struct Declaration {