Fix error for application Procedure type values

Removal of top-arr in the internal representation changed
the error message and we didn't have a test for it.

Closes PR 14601
add missing casts that are required by some C compilers
redex: fix for `render-language` with `extend-language-show-union` as #t

Merging base languages didn't add non-terminals that are included only
in the extension.

Also, add `extend-language-show-extended-order` for showing productions in
the order of an extended language instead of the original language.
fix doc typo
scribble: add `nosearchform` to HTML output without a search box
reference: add "file date and time" index entry

Since `file-or-directory-modify-seconds` is not an obvious function name.
reference & guide: improve explanation of regexp performance

Explain better that regexp values can be used more efficiently
than strings or byte strings as patterns.

Adjust all examples to use regexp values instead of strings.
Initial internal Typed Racket documentation.

Still needs to be scribbled, and have lots more added.
Add syntax properties in contract expansion for TR

This establishes a communication channel between the
contract system and TR. TR normally can't track the
relationship between the identifier bound to the transformer
that produces the lifted value expression (which has the
type in the environment) and the lifted expression
itself.

This also adds properties that indicate which parts are
lifted expressions and if a function has an extra negative
party argument.

Finally, the expansion of keyword arguments is modified
slightly to propagate syntax properties on function argument
syntax to the let-bound identifiers that the keyword application
generates.
Add support for typechecking contracted functions
Add types and tests for racket/format
Add test case from Matthew for ac169edfcf
Fix for/fold typechecking on null accumulator

Closes PR 13259
Make -id-path handle mutable variables correctly.
Make overlap for procedures and simple data stronger.
Improve filters generated for true values in tc-id and tc-let.
Strengthen simplification of filters in tc-subst.
Do not add filters to the prop environment.