LibGUI: clang-format

Author: https://github.com/faissaloo
Commit: 55e115b0cd
Pull-request: https://github.com/SerenityOS/serenity/pull/173
Reviewed-by: https://github.com/awesomekling

LibGUI/GAbstractButton.cpp

@@ -31,7 +31,7 @@ void GAbstractButton::set_checked(bool checked)
     m_checked = checked;
 
     if (is_exclusive() && checked) {
-        parent_widget()->for_each_child_of_type<GAbstractButton>([&] (auto& sibling) {
+        parent_widget()->for_each_child_of_type<GAbstractButton>([&](auto& sibling) {
             if (!sibling.is_exclusive() || !sibling.is_checkable() || !sibling.is_checked())
                 return IterationDecision::Continue;
             sibling.m_checked = false;