minor spelling and typo fixes

[dvklopfenstein]

Checklist

• I've tested that my changes are compatible with the latest version of Tensorflow.
• I've read the Contribution Guidelines
• I've updated the documentation if necessary.

Motivation and Context

Description

[zsdonghao]

Thanks a lot for the contribution, however, I am not able to merge this PR before you update the changelog.md. Could you put your Github and PR IDs in to the changelog.md?

Many thanks.

[dvklopfenstein]

Thank you very much for considering my pull request. I have updated the changelog.md with my GitHub ID and PR

[dvklopfenstein]

Hello,

The error seen in both:

• ci/cirlceci: test_sources_py2_cpu and
• ci/cirlceci: test_sources_py2_cpu

is:

ERROR: No matching distribution found for scikit-learn==0.21.0 (from tensorlayer==2.0.0)

I do not believe my doc change resulted in this error.

MORE INFO: On the scikit web pageScikit-learn from 0.21 requires Python 3.5 or greater, but the tests that are failing are being run with Python 2.7 so perhaps a configuration file needs to be modified to use a different version of scikit-learn when using Python2.7.

I don't want to further edit anything in an attempt to address an ERROR, but am just reporting what I am seeing...