Removed repetitions of "the" in some comments.

Change-Id: I36a6f51609765076de32e1b97398c4c08743aafc
GitHub-Last-Rev: 4d06aea6a787cfca40eda10845897ff149fff62c
GitHub-Pull-Request: golang/go#33797
Reviewed-on: https://go-review.googlesource.com/c/go/+/191497Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>