Style: clang-format: Disable KeepEmptyLinesAtTheStartOfBlocks

Which means that reduz' beloved style which we all became used to
will now be changed automatically to remove the first empty line.

This makes us lean closer to 1TBS (the one true brace style) instead
of hybridating it with some Allman-inspired spacing.

There's still the case of braces around single-statement blocks that
needs to be addressed (but clang-format can't help with that, but
clang-tidy may if we agree about it).

Part of #33027.

core/string_buffer.h

@@ -35,7 +35,6 @@
 
 template <int SHORT_BUFFER_SIZE = 64>
 class StringBuffer {
-
 	CharType short_buffer[SHORT_BUFFER_SIZE];
 	String buffer;
 	int string_length = 0;