Log Message:
bash: update to 5.1.16.

13: Fix ~ expansion after : in assignment statements in POSIX mode.
14: Fix corruption in multibyte chars spanning a 512 byte buffer when
    reading the output of a command substitution
15: Fix sign extension with charsets containing 'negative' chars
16: Make multiple ! in a [[ ]] toggle negation instead of just more of the same

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