Style: Enforce separation line between function definitions

I couldn't find a tool that enforces it, so I went the manual route:
```
find -name "thirdparty" -prune \
  -o -name "*.cpp" -o -name "*.h" -o -name "*.m" -o -name "*.mm" \
  -o -name "*.glsl" > files
perl -0777 -pi -e 's/\n}\n([^#])/\n}\n\n\1/g' $(cat files)
misc/scripts/fix_style.sh -c
```

This adds a newline after all `}` on the first column, unless they
are followed by `#` (typically `#endif`). This leads to having lots
of places with two lines between function/class definitions, but
clang-format then fixes it as we enforce max one line of separation.

This doesn't fix potential occurrences of function definitions which
are indented (e.g. for a helper class defined in a .cpp), but it's
better than nothing. Also can't be made to run easily on CI/hooks so
we'll have to be careful with new code.

Part of #33027.

editor/editor_file_system.cpp

@@ -56,6 +56,7 @@ int EditorFileSystemDirectory::find_file_index(const String &p_file) const {
 	}
 	return -1;
 }
+
 int EditorFileSystemDirectory::find_dir_index(const String &p_dir) const {
 	for (int i = 0; i < subdirs.size(); i++) {
 		if (subdirs[i]->name == p_dir)
@@ -1110,6 +1111,7 @@ void EditorFileSystem::_notification(int p_what) {
 bool EditorFileSystem::is_scanning() const {
 	return scanning || scanning_changes;
 }
+
 float EditorFileSystem::get_scanning_progress() const {
 	return scan_total;
 }