remove use of deprecated hex string literals

[ghost]

This PR removes all uses of hex string literals. It is required if dlang/dmd#6925 is accepted.

[dlang-bot]

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[wilzbach]

LGTM, but this is blocked on @WalterBright's approval to deprecate hex strings

[ghost]

So i let the initiative to someone who'll be stasified by the way things are working here