doc: further explain fill/fill!
rename Uint -> UInt in contrib files for syntax highlighting
Merge pull request #9019 from simonbyrne/uint-contrib

rename Uint -> UInt in contrib files for syntax highlighting
greatly improve performance of closed variables

- avoid undefined var check for closed variables that come from arguments
  (detectable by the fact that the variables are not arguments inside the
  closure, but are never assigned to either)

- use tbaa_const for loads from closure environments. these are never
  mutated; mutable bindings use boxes.
Skip the overhead of tuple construction for CartesianIndex
Merge pull request #9015 from amitmurthy/amitm/filldoc

doc: further explain fill/fill!