* perl: improve matching pattern examples * perl: remove in-place find/replace sans -i'.old' * perl: nix -0 from multiline find/replace example * perl: update wording per code review Co-authored-by: Emily Grace Seville <emilyseville7cf@gmail.com> * perl: update placeholders per code review Co-authored-by: Emily Grace Seville <emilyseville7cf@gmail.com> * perl: update wording per code review Co-authored-by: Emily Grace Seville <emilyseville7cf@gmail.com> * perl: update placeholders per code review Co-authored-by: Emily Grace Seville <emilyseville7cf@gmail.com> * perl: update placeholders per code review Co-authored-by: Emily Grace Seville <emilyseville7cf@gmail.com> * perl: update placeholders per code review Co-authored-by: Emily Grace Seville <emilyseville7cf@gmail.com> * perl: add more -e flag markers, tweak wording Co-authored-by: Emily Grace Seville <emilyseville7cf@gmail.com> * perl: "print out" → "print" Co-authored-by: Emily Grace Seville <emilyseville7cf@gmail.com>