Fix emote completion bug

This commit fixes a bug that would occur when changing the completion
mode from prefix-only to substring while mid-completion.
In that case, the suggestion list was not updated until the next
completion attempt.

This is fixed by forcing a suggestion list refresh whenever the
setting's checkbox is updated.

src/widgets/helper/ResizingTextEdit.cpp

@@ -260,6 +260,11 @@ void ResizingTextEdit::insertFromMimeData(const QMimeData *source)
     }
 }
 
+void ResizingTextEdit::resetCompletionInProgress()
+{
+    this->completionInProgress_ = false;
+}
+
 QCompleter *ResizingTextEdit::getCompleter() const
 {
     return this->completer_;