Recognize missing Begin* or End* functions (eg: GUI.BeginGroup/GUI.EndGroup)

**Hello,**

Unity contains a number of matching Begin/End functions. Like braces, recognize when a Begin* or End* function exists without its counterpart.

Below is what I believe to be a complete list of Unity's begin/end function pairs:

- CommandBuffer.BeginSample/CommandBuffer.EndSample
- CustomSampler.Begin/CustomSampler.End
- EditorGUI.BeginChangeCheck/EditorGUI.EndChangeCheck
- EditorGUI.BeginDisabledGroup/EditorGUI.EndDisabledGroup
- EditorGUI.BeginProperty/EditorGUI.EndProperty
- EditorGUILayout.BeginHorizontal/EditorGUILayout.EndHorizontal
- EditorGUILayout.BeginScrollView/EditorGUILayout.EndScrollView
- EditorGUILayout.BeginToggleGroup/EditorGUILayout.EndToggleGroup
- EditorGUILayout.BeginVertical/EditorGUILayout.EndVertical
- EditorGUILayout.BeginFadeGroup/EditorGUILayout.EndFadeGroup
- EditorWindow.BeginWindows/EditorWindow.EndWindows
- GL.Begin/GL.End
- GUI.BeginGroup/GUI.EndGroup
- GUI.BeginScrollView/GUI.EndScrollView
- GUILayout.BeginArea/GUILayout.EndArea
- GUILayout.BeginHorizontal/GUILayout.EndHorizontal
- GUILayout.BeginScrollView/GUILayout.EndScrollView
- GUILayout.BeginVertical/GUILayout.EndVertical
- Handles.BeginGUI/Handles.EndGUI
- MaterialEditor.BeginAnimatedCheck/MaterialEditor.EndAnimatedCheck
- Profiler.BeginSample/Profiler.EndSample
- Profiler.BeginThreadProfiling/Profiler.EndThreadProfiling

**Thank you for your consideration!**
\- S.