[Trivial] Fix a size_t reference for clang 13
MODIFY
src/veil/mnemonic/dictionary.h
src/veil/mnemonic/dictionary.h
/**
* A valid mnemonic dictionary has exactly this many words.
*/
-static constexpr size_t dictionary_size = 2048;
+static constexpr std::size_t dictionary_size = 2048;
/**
* Dictionary definitions for creating mnemonics.

[Trivial] Fix a size_t reference for clang 13