Style: Enforce braces around if blocks and loops

Using clang-tidy's `readability-braces-around-statements`.
https://clang.llvm.org/extra/clang-tidy/checks/readability-braces-around-statements.html

core/crypto/hashing_context.cpp

@@ -128,6 +128,7 @@ void HashingContext::_bind_methods() {
 }
 
 HashingContext::~HashingContext() {
-	if (ctx != nullptr)
+	if (ctx != nullptr) {
 		_delete_ctx();
+	}
 }