Improve grammar in some comments.

git grep'd for "more then", "less then", "greater then".
(Interestingly, no hits for "fewer then".)

BUG=none
NOPRESUBMIT=true
CQ_INCLUDE_TRYBOTS=tryserver.chromium.linux:closure_compilation;master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2157963002
Cr-Commit-Position: refs/heads/master@{#406059}
34 files changed