Documentation update to reference RE2 as the regex engine in Push Rules UI
Add a reference to RE2 in the UI
In 10.4 using Ruby Regexp was changed to RE2.
To highlight which regex engine is being used. We reference Ruby Regexp but all of that syntax is not supported in RE2
Further details
An example is using \Z is supported in Ruby Regexp but not in RE causing confusion.
Proposal
Change documentation link to RE2.
Links / references
