documentation: fix a typo in Quickstart

[jeras]

I fixed a typo in a CLI and added a cosmetic update to a sentance.

[jeras]

I created this issue before I decided to fix the code and ask for a pull:
#49

[pawks]

Thank you for the PR. A changelog update and version bump is needed to merge this. There seems to be residual mentions of arch-tests in commands.rst. Please replace those too.

[jeras]

Hi Pawan, I am reading the documentation further and will combine all the fixes into a single merge request with an updated CHANGELOG at the end. It will probably take me a week (I am trying to run tests on my CPU at the same time).

[pawks]

This particular entry in the notes can be removed as the database is generated every time for each riscof run. It can probably be modified to:

3. The database file is generated by default every time for any relevant command unless a ``--database`` argument is supplied in the command. 
4. Each time a new test is added to the ``suite`` directory, the database utility has to be run  to ensure that the test is included in the ``database.yaml``. This can be done by running the `gendb` command or by skipping the ``--database`` argument in the CLI for relevant commands. 

[jeras]

I will have a look at it this weekend.

Otherwise I still have some documentation files to go through, before the changes would be ready for a merge.

I have split the changes into multiple commits, so they are easier to review.
Every find/replace (for capitalization) has its own commit, and I will try to split remaining changes into:

• fixed width font,
• spelling and grammar,
• functionality.

I did not make changes to the Python source code, although there are many cases with missing capitalization.
Consequentially I also did not make changes to code blocks in the documentation.