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.

core/dictionary.cpp

@@ -79,6 +79,7 @@ Variant &Dictionary::operator[](const Variant &p_key) {
 const Variant &Dictionary::operator[](const Variant &p_key) const {
 	return _p->variant_map[p_key];
 }
+
 const Variant *Dictionary::getptr(const Variant &p_key) const {
 	OrderedHashMap<Variant, Variant, VariantHasher, VariantComparator>::ConstElement E = ((const OrderedHashMap<Variant, Variant, VariantHasher, VariantComparator> *)&_p->variant_map)->find(p_key);
 
@@ -115,6 +116,7 @@ Variant Dictionary::get(const Variant &p_key, const Variant &p_default) const {
 int Dictionary::size() const {
 	return _p->variant_map.size();
 }
+
 bool Dictionary::empty() const {
 	return !_p->variant_map.size();
 }
@@ -170,6 +172,7 @@ void Dictionary::_unref() const {
 	}
 	_p = nullptr;
 }
+
 uint32_t Dictionary::hash() const {
 	uint32_t h = hash_djb2_one_32(Variant::DICTIONARY);
 
@@ -254,6 +257,7 @@ Dictionary::Dictionary() {
 	_p = memnew(DictionaryPrivate);
 	_p->refcount.init();
 }
+
 Dictionary::~Dictionary() {
 	_unref();
 }