Keep commentLocations on SourceModule for definition files (#1314)

Right now, the commentLocations are not transferred over to the
SourceModule for definition files, like they are for normal source
modules. This means we lose out on finding documentation comments. We
add that in here

#1137 (comment)

Analysis/src/Frontend.cpp

@@ -35,6 +35,7 @@ LUAU_FASTINT(LuauTarjanChildLimit)
 LUAU_FASTFLAG(LuauInferInNoCheckMode)
 LUAU_FASTFLAGVARIABLE(LuauKnowsTheDataModel3, false)
 LUAU_FASTFLAGVARIABLE(LuauCancelFromProgress, false)
+LUAU_FASTFLAGVARIABLE(LuauStoreCommentsForDefinitionFiles, false)
 LUAU_FASTFLAG(DebugLuauDeferredConstraintResolution)
 LUAU_FASTFLAGVARIABLE(DebugLuauLogSolverToJson, false)
 LUAU_FASTFLAGVARIABLE(DebugLuauLogSolverToJsonFile, false)
@@ -127,6 +128,12 @@ static ParseResult parseSourceForModule(std::string_view source, Luau::SourceMod
     Luau::ParseResult parseResult = Luau::Parser::parse(source.data(), source.size(), *sourceModule.names, *sourceModule.allocator, options);
     sourceModule.root = parseResult.root;
     sourceModule.mode = Mode::Definition;
+
+    if (FFlag::LuauStoreCommentsForDefinitionFiles && options.captureComments)
+    {
+        sourceModule.hotcomments = std::move(parseResult.hotcomments);
+        sourceModule.commentLocations = std::move(parseResult.commentLocations);
+    }
     return parseResult;
 }