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
JIT: fix slow-path boxing for non-self-tail calls with unboxed arguments

The bug was introduced when changing the order of unboxed argument
staging along with extflonum unboxing support. The main symptom of
the bug was that icons were sometimes blacked out in DrRacket.
version 5.3.3.5

Bumped to force a rebuild of ".zo"s that were generated with the flonum
bug.
add space before "View Prior Versions"
fix bug in getting "rest" of an integer-set
add test for integer-set:

- check that taking the rest of an integer-set results in a proper integer-set
one more integer-set test
Note that integer-sqrt produces exact output when given exact input.

Closes PR 9542.
Add reference to the DrRacket interface essentials from the Quick Start guide.

This adds a tag to DrRacket File menu docs.  It adds two margin notes
to the quick start, one linking to the essentials for using DrRacket,
and the other for saving Definitions.

Addresses PR 9501.
tweak