Remove oppressive language in comment.

The comment can be removed because crbug.com/855192 and its canonical
crbug.com/872096 are closed (obsolete).

Bug: b:163002438
Change-Id: I7ef1c7854cb82a3855fd0d09f7d0ccaef0daa112
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2340924Reviewed-by: Jia Meng <jiameng@chromium.org>
Commit-Queue: Claudio M <claudiomagni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#795749}

components/language/core/browser/language_model_manager.cc

@@ -11,7 +11,6 @@ namespace language {
 LanguageModelManager::LanguageModelManager(PrefService* prefs,
                                            const std::string& ui_lang)
     : primary_model_type_(ModelType::BASELINE) {
-  // TODO(crbug.com/855192): put code to add UI language to the blacklist here.
 }
 
 LanguageModelManager::~LanguageModelManager() {}