this also gets rid of the module-level imports as annotations in the bar
along the buttom of a drracket window, which eliminates the use of the
'drracket:check-syntax:mouse-over status line and thus:
closes PR 12186
being edited in DrRacket (via places)
Added an API to let tools have access to that
information (and compute more stuff)
Used that to make an online version of Check Syntax
which led to a separately callable Check Syntax API.
queue-callback / execute callback dance; also, change the behavior
a little bit so that it works a little bit more like the rest of the
DrRacket languages; in particular, the initialization of the REPL
now only happens when a window is first opened or a new tab is first
created, but not at other times (ie not when the language changes;
when the language changes, we just keep the REPL state the same and
show a warning like before)
This change also required a change to the way the repl is initialized
and a slight change to the behavior of the first-opened method. Specifically,
it is now called in a slightly better context so that errors that
happen look like errors in the user's program. The only other use of
the first-opened method in the tree was to initialize the teachpacks
in the teaching languages and this new behavior is also an improvement
there.
including adding some uses of `with-module-read-parameterization'
so that `read-accept-lang' is set right anyway; still, so many
many places just set `read-accept-reader' to #t that making
`read-accept-lang' #f by default looks like too big of an
incompatibility
