Version number for the v5.3.3 bugfix release
fix a bug in highlight-range exposed by the contour window

closes PR 13488
related to PR 13491
(cherry picked from commit deac3fa2b30a45d0945f895f4181d916df922b58)
a better version of deac3fa2b30a45d0945f895f4181d916df922b58

This time with test cases, and also without changing the
semantics of unhighlight-range

related to PR 13488
(cherry picked from commit e7e64f400622d1d23051616128ff246c857ab32e)
add v5.3.3 notes
(cherry picked from commit dfed25cfe1cbf7f886836c18611201fb8c6d9f29)

Conflicts:
	doc/release-notes/racket/HISTORY.txt
New Racket version 5.3.3.
adjust contour to track edit sequences better

Specifically when there is no delegate and an edit
sequence is started, track that differently in case
a delegate is set before the edit sequence ends
(in which case we don't want to end the edit
sequence in the delegate since we didn't start it
there)

related to PR 13491
(cherry picked from commit 405e51bb053c5bce7b972d47706ab81ac136edd7)
v5.3.3 installers info
(cherry picked from commit 173f2896bd52745f202fdc56e6dd25c9afdef847)