added core/modules/widgets/fieldradio.js
Merge branch 'fieldradio' of https://github.com/Skeeve/TiddlyWiki5 into Skeeve-fieldradio
Typo correction
Coding style consistency
Rename 'fieldradio' widget to just 'radio'

We’ve already got two widgets starting “field…”, and “radio” is more
consistent with the existing “checkbox” widget.
Complete renamign the 'fieldradio' widget to 'radio'
Remove file mistakenly included in previous commit
Complete renaming the radio widget
More style adjustments
Docs for the radio widget