Fix #152, Correct typos in documentation, print statements, and comments

[thnkslprpt]

Describe the contribution

• Fix #152

Fixed a few minor typos in the text of:

• README.md
• SECURITY.md

...and in the comments of:

• unit-test/CMakeLists.txt

...and in an assert error message string of:

• unit-test/coveragetest/coveragetest_sample_app.c

Testing performed Only automated checks.

Expected behavior changes None (minor Markdown doc, comments changes, and assert error string changes that do not interact with any max lengths etc.).

System(s) tested on n/a

Additional context n/a

Code contributions n/a

[astrogeco]

Tested in https://github.com/astrogeco/sample_app/commit/847ba8e09d2a90ba16466b87bce66236f8c62ffe

Merged in 847ba8e09d2a90ba16466b87bce66236f8c62ffe