Fix return tc-results when typechecking kw lambda.
fix mailing list link

closes PR 14491
adjust angle->proper-range based on Neil's advice
Rackety (102 columns)
remove printf
Fix typo in symbols.scrbl
setup/dirs et al.: thread-safe promises

Use `delay/sync` instead of `delay`.
ffi/unsafe: correct and improve docs on `_cpointer`
fix doc header
fix bug in flat struct/dc predicate implementation
contract improvements

- add a generator for cons/c
- make flat-rec-contract not just build the predicate, meaning:
  - it has a better name
  - it can do random generation
- make the procedures that come from any/c random generation indicate that from their names
- make or/c with one argument just (check and) return that argument, so
  (or/c (or/c number?)) has the name 'number?'
add a random generator for struct/c

This is actually done by adding a generator for struct/dc in the case
that there are no dependencies, so it'll also work for such contracts.
Fix type printing for simple latent filters

Don't print a simple filter for a function with more than
one argument or with a filter object that refers to an outer
variable.

This matches up with type parsing.

Closes PR 14510
Make tc-lambda not internal error in poly dotted expected contexts.
Abstract over dotted type in values.
Make valuesdots subtyping not cause contract violations.
Make inst fail on results that are not single valued.
default module name resolver: fix cache

The cache was keyed on `current-library-collection-paths`, but
not other parameters such as `current-library-collection-links`,
so it was too "sticky" in the case that some parameters changed.
Adjust the cache to be specific to loaded module in a namespace's
module registry.
scribble/base: add `#:style` argument to `image`
scribble docs: fix example for `literal`