* Lint: Disable a couple potentially problematic/unneeded hooks
* Lint: Refine regex for existing Content-Type and PEP references checks
* Lint: Refine regex for Python-Version check and fix a couple deviations
* Lint: Refine regex for Created check and fix a couple deviations
* Lint: Refine regex for Resolution check and fix a few deviations
* Lint: Add new check for Post-History header
* Lint: Add check for Discussions-To header link
* Lint: Add basic check for PEP title presense & excessive length
* Lint: Add check for PEP/BDFL-Delegate header
* Lint: Add check for Sponsor header
* Lint: Add check for legacy Author field format
* Lint: Add check for RST Author field
* Lint: Use more helpful, user-oriented descriptions for header checks
* PEP 245: Add historical note and archive links to wiki page/email lsit
* PEP 628: Add direct link to resolution in acceptance message
* Lint: Explictly allow all valid RFC 2822 line continuations in headers
* Lint: Tweak Post-History and Resolution checks to accept fragments
These two PEPs were listed as rejected alternatives when PEP 465's
matrix multiplication operator was accepted and implemented, but
still marked as Deferred in the PEP listing.
This updates their headers to indicated their Rejected status,
with a link to the relevant section of PEP 465 as their resolution
reference.