New Racket version 5.3.3.4.
JIT: inline `char->integer' and `integer->char'
racket/draw win32: work around a Pango bug

Pango crashes (with an assertion failure) on characters U+1D173
through U+1D17A. Trying to fix (or even just compile) Pango for
Windows is hard, so skip the characters at the `draw-text' and
`text-extent' level.

The bug is unlikely to be specific to just those characters in the
long run, but only those characters appear to be problematic on my
Windows 7 installation. So, the workaround may be enough for many
installations, and hopefully the Pango bug wil be fixed one day.

Relevant to PR 13513
add ackn
JIT: fix for 32-bit mode

Fix a bug in ca951294d4.
Add example of mixin form to guide documentation.

Closes PR 13445.
use impersonator-ephemeron to allow a
real contract on preferences:add-callback
adjust the c:x;n and c:x;p keybindings to use the
same information as the yellow green bubbles

Before, when you typed c:x;n, drracket would look at the identifier
you're on, find its binder, find all bound occurrences of that binder,
sort them by position in the buffer, and then jump to the one that
follows where you are.

This works great for things like the "x" in "(let ([x 1]) x x)"
but not so great for things like the "define" in:

  #lang racket
  (define x '(+ 1 2))
  (define y '(+ 3 4))

since that would jump to the quote, since there are bindign arrows
going from the "racket" to the define and to the quote.

Now, since it is using information ultimately derived directly
from (and only from) free-identifier=? (the arrows also come from
identifier-binding, which is how we get those arrows in the second
example above) you jump from the first define to the second define,
which seems better.
Adding link to prior versions of the docs.
scribble/sigplan: add `subtitle'

Based on David Van Horn's suggestion.

Also, make both `author' and `authorinfo' work (even when mixed).
another JIT repair
scribble: fix 'aux stripping for hyperlinks and HTML titles
Rackety
Minor doc fixes
Index some info.rkt fields for raco setup
fix error checking for `flreal-part' and `flimag-part'
racket/extflonum: fix JIT-inlined `extflvector-ref' in 32-bit mode
fix non-extflonum build
remove spurious printf
signal error when attempting to generate from a
metafunction with no cases

closes PR 13536