[MERGE] debugs message improvement: use HERE macro wherever sensible

Hi all,
  at lp:~kinkie/squid/sourceformat I have a work branch aiming at
using HERE in debugs() messages wherever sensible.
Apart from the main goal, there's a few typo fixes and a few wording
improvements. No functional changes.
The patch is ~11k lines so far, with ~1400 changes, I'm about halfway through.
Any preference on how to review? Or may I just commit once it passes a
full testsuite build?

Thanks

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    /kinkie