Revert "doc fixups for `struct' variants in `scheme/unit', etc."

This reverts commit 3ded3934ee0a650fa2f3d180d7f3a56cab9af4b8.
Revert "Update props file for `racket/private/shared-body.rkt`"

This reverts commit 68d550e2c39b592a235b8c04ce5a9417c6aa5c10.
Revert "Fix unit test broken by mzlib movement"

This reverts commit 3158acd61d5b367544932b4d4df61c2fa4b91491.
Revert "Moved some mzlib library implementations to racket"

This reverts commit 403aaac7d4c32132223f06e059df439cceda7a2e.

Conflicts:
	collects/racket/place.rkt
bring the language test up to date with the latest error messages

include in the release branch, please
(cherry picked from commit 8744cd781122379bf61cdc83a0c2620e3058fee5)
adjusted the repl test suite for the new error messages
and the change to the racket/gui load-handler

(unfortunately, there is still another problem that keeps
the test suite from passing)

please merge to the release branch
(cherry picked from commit d8204b1624b42ba5efec8a8923276f7bec6dd417)
module lang test now up to date with error message changes

please include in release branch
(cherry picked from commit 17594ec804a84cec786d00da8de579696a723828)
typo
(cherry picked from commit a3b316c02f44809d0dda5b76e587149403493714)
racket/gui/init: fix load handler
(cherry picked from commit b111241afebefe801280c6633474d96e88a6cf68)
Add missing meta information for the new "future-visualizer" collection.
(cherry picked from commit 1635ac1bc524fa4eff1379624cd7826e7a0684e9)
Make it possible to use "~" or "~user" in the installer.

I've looked for a while, and it seems that there is no easy way to do
this, not even in bash, and worse with /bin/sh.  So this is kind of
resorting to a simple parsing of the input, and using `eval' if it
starts with a tilde.  Note the hack of not doing that when there is a
space, otherwise the `eval' thing will silently ignore it.

This hack means that it's easy to get into a mess if quotes are used
after a tilde, but that was already the case with the use of `eval' to
handle environment variables.  It's not a real security issue, however,
since we're talking about a user who can just run any command anyway.

Also including a test file for the expansion functionality.  If anyone
wants to improve this code, making the tests pass would reveal the
tricky issues.

[FWIW, I've asked on the #bash channel, and the only serious suggestion
was getting the paths as command-line arguments.  This will, however,
defeat the point of being newbie friendly...]

Closes PR 12893.
(cherry picked from commit 0814fd5fb5f660bc9698f21445976902317291d1)
Disable the `#:before-first' and `#:after-last' functionality in `add-between'.

Leave it working in splicing mode.  I prefer doing that over always
splicing them, since that would make a less uniform interface, so I
rather keep all options open.  There is no longer a `#:nothing' keyword,
which is the main point of this downgrade.

(See mailing list discussion on "no-argument" for the reason.)
(cherry picked from commit 6565538b092ee082af1e2effa22c4b0ceb1b9f1a)
Fix typo from commit 12a4ee8.
(cherry picked from commit 36ee9f9bbd2ccf05c17329e7414ba54a9e0d9aab)
fixed repl-test-misc.rkt for the error message changes

please include on the release branch
(cherry picked from commit ef5c2b825fd029d2f6a9033623233b820842dfbf)
bring back drscheme/private/number-snip.ss since it may
appear in saved wxme format files

also, improve the testing support for testing snip loading
(before this, the testing infrastructure could let one test
"leak" into another one in a way that could mask failures)

please include in release branch
(cherry picked from commit b342009e7186f6a3d535670d9b5164e83b7a6940)
collapse Racket history for v5.3 release

Merge to v5.3
(cherry picked from commit 27d729c3ff418a0b82e580b5b5b4cc3bce043bc4)
fix related to module name resolver change
(cherry picked from commit 9413b30599be8aa3c990a67448833f643bcd1f4a)
Document `Struct`.

Merge to release.
(cherry picked from commit a589d027511c3a609ffbda2efaaf394c2734c1bc)