racket/gui cocoa: repair for canvas creation in hidden top-level window

Fixes 9cb646bbd2 for the case that a frame or dialog is shown,
then hidden, then a new canvas is created or a new compatible
bitmap is requested via the `make-bitmap` method.

The test for this change is just the "windowing.rktl" test, which I
forgot to run before (as opposed to the drawing test suite).
adjust the normalize-paste mixin to, by default,
replace non-breaking minus characters with hyphens

closes PR 14197
racket-doc/scribblings/raco/config.scrbl: typo
adjust multi-file search to make it support searching in multiple directories

Also, add a button that populates the directories from collections and
refactor it to make the "configure search" dialog easier to work with,
ie so it can be run without starting up drracket
Fix format string for GC debug log message

Closes PR 13998

Please merge to v6.0
fix problems with text-mode ports on Windows

Closes PR 14198

Merge to v6.0
racket/gui cocoa: fix flipped drawing for `combo-field%` content

This was another bug in 9cb646bbd2.
fix ODBC numeric/decimal param precision and scale
  closes PR 14171

But wasn't able to get numeric/decimal working on "SQL Server" driver,
only "SQL Server Native Client" driver.
Fix PR14194
Convert readline to Racket

Also lighten package dependencies by removing
scheme-lib and compatibility-lib.
Fix xrepl test (updated expected interactions)
Fix props for xrepl tests

These tests weren't getting run, possibly due to
a change in defaults.
Fix props mistake in 0bafa882bf

Sub-path was unsorted.
Fix typo in engine docs.
Adding user-agent as some services require
Add an example paper for scribble/lncs docs

Please merge to v6.0
Minor formatting fix for ae641cdfc539

Please merge to v6.0
add a shortcut to file|revert
GUI doc fixes

Two of the contracts were inaccurate and, if true, would
have violated subtyping between editor<%> and text%.

Please merge to v6.0
Revert "Ensure that threads created within call-with-limits are accounted during the time/space limits"

This reverts commit 79f8636e1e1d7c141ab3d658b41d7e85964097c8.