Add I18n localization shortcut "l" alongside "t"

[goulvench]

This is a 🙋 feature or enhancement.
This is a 🔦 documentation change.

Notes:

• I haven't found tests for I18n.t that I could duplicate, but maybe I haven't looked in the right places. I'm not familiar with minitest.
• I've adjusted the documentation.
• The ci/build script cannot run on my machine, rbenv refuses to compile ruby 2.7.2.
• While browsing the code, I sumbled upon date_to_string and date_to_long_string, which could be rewritten using I18n.

Summary

Add l filter/tag/shortcut to I18n.l.

Context

Closes #753

[brandondrew]

@goulvench I am guessing that the issue with Ruby 2.7.2 is that you're on a Mac with Apple Silicon (M1 or M2) and that's before Ruby was released with support for Apple Silicon. (I know I was unable to run 2.6.6 for that reason, and I was able to run 2.7.7, but I don't know exactly where the cutoff was.)

@jaredcwhite did you want to keep an old version of Ruby running the CI just to establish that such an old version will work?

Would it be worth considering making 3.x a minimum for Bridgetown 1.3.0? (Or at least 2.7.8?)

[goulvench]

@brandondrew It's not an Apple silicon issue, I used to run ruby 2.5 a couple years ago but scrapped it since I no longer had any project using it. The issue is a null pointer crash when compiling md5.c, but since ruby 2.7.2 is past EOL and CI runs fine I'm gonna leave it at that :-)