Copy edit cli-test-debug.md

Copy edit for consistent tense across docs and minor grammar nits.

Author: Amanda Butler

docs/tools/offline/cli-test-debug.md

@@ -193,27 +193,27 @@ You can specify to only **run** the unit tests by using the `--run` option:
 $ mbed unittest --run
 ```
 
-If you do not specify any of these, `mbed unittest` will build all available unit tests and run them.
+If you do not specify any of these, `mbed unittest` builds all available unit tests and runs them.
 
 ### Running a subset of tests
 
-You can run a **limited set** of unit tests by using the `-r` or `--regex` option. This takes a regular expression, which it compares against the test names. For example to run all cellular unit tests you can specify:
+You can run a **limited set** of unit tests by using the `-r` or `--regex` option. This takes a regular expression, which it compares against the test names. For example, to run all cellular unit tests, you can specify:
 
 ```
 $ mbed unittest -r cellular
 ```
 
 ### Getting code coverage
 
-You can generate a code coverage report by using the `--coverage` option. For example to create an html report you can specify:
+You can generate a code coverage report by using the `--coverage` option. For example, to create an html report, you can specify:
 
 ```
 $ mbed unittest --coverage html
 ```
 
 ### Creating new unit tests
 
-All unit tests are under `mbed-os/UNITTESTS` directory. You can **generate** the necessary files for a unit test by using the `--new` option. For example to create the files for `rtos/Semaphore.cpp` you can specify:
+All unit tests are under the `mbed-os/UNITTESTS` directory. You can **generate** the necessary files for a unit test by using the `--new` option. For example, to create the files for `rtos/Semaphore.cpp`, you can specify:
 
 ```
 $ mbed unittest --new rtos/Semaphore.cpp