Globally replace "hackage.haskell.org" with "ghc.haskell.org"
grammar fix
Remove a couple of unnecessary/outdated references to HBC
Clarification in the docs for INLINE

People often jump to the conclusion that functions aren't inlined
unless you say INLINE, so clarify the documentation to emphasize the
fact that you shouldn't normally need to use INLINE unless you need to
override the defaults.
Add back a comment that got lost
Add layout to MultiWayIf (#7783)

This makes it possible to write

x = if | False -> if | False -> 1
                     | False -> 2
       | True -> 3

Layout normally inserts semicolons between declarations at the same
indentation level, so I added optional semicolons to the syntax for
guards in MultiWayIf syntax.  This is a bit of a hack, but the
alternative (a special kind of layout that doesn't insert semicolons)
seemed worse, or at least equally bad.
comment update