Typo in docs
Typo in docs

Spelling mistakes fixed,

 * identiy > identity
 * suprising > surprising

Reviewers: austin, bgamari

Reviewed By: bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D1871

(cherry picked from commit 02e3ce0bc65f586376c3d2ecab498a4c5a3f6a54)

GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc