Correct various documentation typos

Some of the documentation had the right explanation but the incorrect
function names attached.

Change-Id: I7b479dae6d71a5ac7bc86df5a3890508c3b3d09f
Reviewed-on: https://boringssl-review.googlesource.com/5090
Reviewed-by: Adam Langley <agl@google.com>
13 files changed