Add "UTF support" as a row in the Feature Comparison table

[n1vux]

To do:

• research which of Ag, Rg, Git Grep, Gnu Grep respect LC_*/Locale and otherwise can handle UTF-8 wide char / UTF16BOM/LE/BE / UCS / UTF32 files, mixed or uniform , and
• list those capabilities in a UTF support row on the Feature Comparison page.

(Ack gets (a) ASCII, Latin 1, & singlebyte UTF8 only, plus Workarounds : link #107 FAQ entry )

[n1vux]

Another comparison we might want to link to Linode: 6 Tools to Search Source Code for Developers in Linux mentions

• pt Platinum Search pt (obvious play on Ag silver) "similar to ack and ag ...written in Go" as doing UTF-8, but also EUC-JP and Shift_JIS (doesn't say anything about UTF-16,32)

• git-grep A Spanish language page "RG kills grep AG and Ack" compares timings and shows explicitly prefixing LC_ALL=en_US.UTF-8 git grep to enable unicode in Git-Grep . (That may well be one's default LC_ALL locale on Linux. Also note that Git-Grep will only diff files under Git control.)

• gnu grep in LC_ALL=en_US.utf8 locale will match the han UTF8 chars in ack3#222 as [[:alpha:]]' , but not with LC_ALL=en_US.ASCII`.

To be continued ...