Add form-feed and vertical tab to trim defaults

[NotsoanoNimus]

Add a few extra characters to the collection of default whitespace values in String trim methods.

See: C++'s std::isspace and C's isspace.

[lerno]

I know it's tradition, but no one uses those.

[NotsoanoNimus]

I know it's tradition, but no one uses those.

But what if someone did? 😏

jokes aside, it would be good to grab as much actual ASCII whitespace as possible with the default value, right?

[lerno]

No, because it makes the filtering slower in this implementation. It's O(n) based on length.

[lerno]

Not that it will matter that much. If we used character sets directly it would be faster. I can make a fast trim that outperforms the current one by a factor 3.

[NotsoanoNimus]

Alright, I'm now finished amending this pull request.

I added/fixed the benchmark (as well as the bench runtime). It now lines up with what you posted in Discord, per our discussion there.

Main takeaway: AsciiCharset is the clear victor for trimming regardless of the set size, but the charset trimming gets exponentially faster the larger the filter set is.

----------------------------- BENCHMARKS ------------------------------
Benchmarking string_trim_wars::trim_control ...................... [COMPLETE] 59.32 nanoseconds, 120.02 CPU clocks, 16777216 iterations (runtime 995.15 milliseconds)
Benchmarking string_trim_wars::trim_whitespace_default ........... [COMPLETE] 101.85 nanoseconds, 205.36 CPU clocks, 16777216 iterations (runtime 1.71 seconds)
Benchmarking string_trim_wars::trim_whitespace_default_ordered ... [COMPLETE] 80.39 nanoseconds, 161.45 CPU clocks, 16777216 iterations (runtime 1.35 seconds)
Benchmarking string_trim_wars::trim_whitespace_bad ............... [COMPLETE] 128.67 nanoseconds, 259.01 CPU clocks, 16777216 iterations (runtime 2.16 seconds)
Benchmarking string_trim_wars::trim_whitespace_ordered_extended .. [COMPLETE] 117.15 nanoseconds, 235.81 CPU clocks, 16777216 iterations (runtime 1.97 seconds)
Benchmarking string_trim_wars::trim_charset_whitespace ........... [COMPLETE] 94.11 nanoseconds, 189.68 CPU clocks, 16777216 iterations (runtime 1.58 seconds)
Benchmarking string_trim_wars::trim_many ......................... [COMPLETE] 242.63 nanoseconds, 486.38 CPU clocks, 16777216 iterations (runtime 4.07 seconds)
Benchmarking string_trim_wars::trim_charset_many ................. [COMPLETE] 168.14 nanoseconds, 338.05 CPU clocks, 16777216 iterations (runtime 2.82 seconds)