0.21 · `regex`, `ensure`, `fit`…

from our changelog:

• 0.21, November, 2023:
  • added the regex key argument to split, rsplit, split-omit-nulls.
• August, 2023:
  • added the regex key argument to the replace-* functions.
• March, 2023:
  • added str:ensure, str:ensure-prefix, str:ensure-suffix, str:ensure-wrapped-in and str:wrapped-in-p.
• January, 2023: added the :char-barg parameter to trim, trim-left, trim-right.
  • minor: ends-with-p now works with a character.
• June, 2022: small breaking change: fixed prefixp when used with a smaller prefix: "f" was not recognized as a prefix of "foobar" and "foobuz", only "foo" was. Now it is fixed. Same for suffixp.
• Feb, 2022: added fit: fit the string to the given length: either shorten it, either padd padding.
• 0.20, May, 2021: added ascii-p.