refactor: Improve ordering of headers with clang-format (#5343)

Removes all manual header groupings from source and header files by leveraging clang-format options.

include/xrpl/beast/hash/xxhasher.h

@@ -21,6 +21,7 @@
 #define BEAST_HASH_XXHASHER_H_INCLUDED
 
 #include <boost/endian/conversion.hpp>
+
 #include <xxhash.h>
 
 #include <cstddef>

include/xrpl/protocol/STLedgerEntry.h

@@ -124,4 +124,4 @@ STLedgerEntry::getType() const
 
 }  // namespace ripple
 
-#endif
+#endif