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.

platform/android/file_access_jandroid.cpp

@@ -123,6 +123,7 @@ uint8_t FileAccessJAndroid::get_8() const {
 	get_buffer(&byte, 1);
 	return byte;
 }
+
 int FileAccessJAndroid::get_buffer(uint8_t *p_dst, int p_length) const {
 	ERR_FAIL_COND_V_MSG(!is_open(), 0, "File must be opened before use.");
 	if (p_length == 0)