[commit: ghc] wip/branchedness's head updated: Add explaining comment (d7c6a64)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

Branch 'wip/branchedness' now includes:

     a66e1ba User's guide: delete ancient "Core syntax" example
     7cf87df Fix #7919 (again)
     353db30 Remove checked-in PDFs.
     8f81af9 Typos in comments
     ad089f5 Give raise# a return type of open kind (#10481)
     75504f3 Typos in comments
     15dd700 Replace (SourceText,FastString) with StringLiteral data type
     1634c3c Make BranchFlag a new kind, resolving an old TODO comment
     9364d27 Typo
     d7c6a64 Add explaining comment