LibGUI: Remove now-unused undo coalescing timer from GUI::TextEditor

This is no longer used since commands handle merging themselves.

Userland/Libraries/LibGUI/TextDocument.cpp

@@ -34,11 +34,6 @@ TextDocument::TextDocument(Client* client)
                 client->document_did_update_undo_stack();
         }
     };
-
-    m_undo_timer = Core::Timer::create_single_shot(
-        2000, [this] {
-            update_undo();
-        });
 }
 
 TextDocument::~TextDocument()
@@ -316,9 +311,6 @@ void TextDocument::update_views(Badge<TextDocumentLine>)
 
 void TextDocument::notify_did_change()
 {
-    if (m_undo_timer)
-        m_undo_timer->restart();
-
     if (m_client_notifications_enabled) {
         for (auto* client : m_clients)
             client->document_did_change();
@@ -846,11 +838,6 @@ void RemoveTextCommand::undo()
     m_document.set_all_cursors(new_cursor);
 }
 
-void TextDocument::update_undo()
-{
-    // FIXME: Maybe seal the last command somehow?
-}
-
 TextPosition TextDocument::insert_at(const TextPosition& position, const StringView& text, const Client* client)
 {
     TextPosition cursor = position;

Userland/Libraries/LibGUI/TextDocument.h

@@ -132,8 +132,6 @@ protected:
     explicit TextDocument(Client* client);
 
 private:
-    void update_undo();
-
     NonnullOwnPtrVector<TextDocumentLine> m_lines;
     Vector<TextDocumentSpan> m_spans;
 
@@ -141,7 +139,6 @@ private:
     bool m_client_notifications_enabled { true };
 
     UndoStack m_undo_stack;
-    RefPtr<Core::Timer> m_undo_timer;
 
     RegexResult m_regex_result;
     size_t m_regex_result_match_index { 0 };