fixups for `pict' and `slideshow' docs
minor doc fixes
fix problem in `free-identifier=?'

Renamings created by a rename-transformer binding were not treated
correctly by `free-identifier=?'.

Closes PR 12623
Fixing PR13748
Redex enum supports var-except.

Also reduces code duplication in Redex enum.
Redex enum maintains bijection internally

Also simplified other redex enumeration internals.
Added holes to redex enumerator.
Redex generator supports mismatched names.

Also added mismatched name tests.
fix object/c's blame context manipulations

Specifically,
- add field and method contexts, and
- declare methods in object/c contracts to be #:important

closes PR 13765
Fixes PR13750
Cue user about unexpanded type aliases

This tells the user that more type aliases are
available for expansion. For example, (Listof Number)
has the alias Number still unexpanded into the union
that it represents.
Expend printing fuel in all branches

This makes (:type (Number -> Integer)) produce
(Number -> Integer) instead of expanding at the first name.
Combined with expansion cues, this makes it easier for users
to expand the relevant parts of types.
Fix alarm-evt doc typo
remove now-redundant tests
Re-enable redex's overlapping arrows src loc information

This reverts commit e5a84eff8d3a14776e10defebca93b56cc2ccb50.
and also uses the property 'original-for-check-syntax
indent
Use random for changes
Don't check name if not given
Document :type better
Update the instructions on configuring git's push.default.