raco test: fix `-l`
raco test: show more of stderr on failure
syntax-color/lexer-contract: make random-test failure declare itself

Random tests that are implciitly injected into a program should
declare themselves as such when they fail. Otherwise, random
crashes are really confusing.
syntax-color/racket-lexer: fix problem with unclosed "| "

... where the whitespace character after "|" is non-ASCII.

This bug was found by random testing in `syntax-color/lexer-contract`.
racket/udp: adjust receive into a zero-sized buffer

The OS doesn't necessarily react to a zero-sized buffer the way
that `udp-receive!` is supposed to work, so provide only a
non-zero-sized buffer to the OS.
correct `register-finalizer` docs by clarifying prohibitions
pkg manage docs: clairfy in overview that a git repo tag is allowed
Inside Racket: document Windows-specific treatement of "UTF-16"
openssl: fix `ssl-load-default-verify-sources!` for Win64

Closes PR 14784

Merge to v6.1.1