Style: Remove unnecessary semicolons from core

Semicolons are not necessary after function definitions or control flow
blocks, and having some code use them makes things inconsistent (and
occasionally can mess up `clang-format`'s formatting).

Removing them is tedious work though, I had to do this manually (regex
+ manual review) as I couldn't find a tool for that. All other code
folders would need to get the same treatment.

core/object.cpp

@@ -1000,7 +1000,7 @@ void Object::set_meta(const String &p_name, const Variant &p_value) {
 	if (p_value.get_type() == Variant::NIL) {
 		metadata.erase(p_name);
 		return;
-	};
+	}
 
 	metadata[p_name] = p_value;
 }