Minor improvements in grammar and clarity

[galtm]

Committer Notes

While reading this readme document, I found a few ways to improve it. I'm not sure I am using the correct branch for this PR, so let me know if I should use a different branch instead.

Closes #1822.
Closes #1826.
Closes #1829.
Closes #1833.
Closes #1834.
Closes #1835.
Closes #1836.
Closes #1837.
Closes #1838.
Closes #1840.

All Submissions:

• Have you selected the correct base branch per Contributing guidance?
• Have you set "Allow edits and access to secrets by maintainers"?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• Have you squashed any non-relevant commits and commit messages? [instructions]
• Do all automated CI/CD checks pass?

By submitting a pull request, you are agreeing to provide this contribution under the CC0 1.0 Universal public domain dedication.

(For reviewers: The wiki has guidance on code review and overall issue review for completeness.)

Changes to Core Features:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your core changes, as applicable? N/A
• Have you included examples of how to use your new feature(s)? N/A
• Have you updated all OSCAL website and readme documentation affected by the changes you made? Changes to the OSCAL website can be made in the docs/content directory of your branch. N/A

[aj-stein-nist]

Thank you so much for looking at this @galtm and bringing it to our attention. I had not read this page in a long while. I appreciate your copy editing contributions and want to keep the first part, but can we remove the rest of the document? A lot of it is useful, but reudnant with the MIMF site, so I would rather just point them to the source and reduce churn on docs (for instance, we don't have only five models anymore in current releases, but Metaschema changes will be document on their site, I'd rather focus on working with the relevant primary copy of that information. 😄)

[aj-stein-nist]

Also note for the me and the rest of the team if they see this PR: it may need amendment when the upcoming release-1.0 branch is pushed into main to "sync" them and I will help adjust this PR accordingly for a potential merge conflict iff necessary, thanks again!

[galtm]

Now that the 2nd commit replaces much of the content with a link, does this PR now address #1830 ?

[aj-stein-nist]

Looks good and thanks for this, @galtm. Need to do some bookkeeping before merge. I welcome review from other team members as well.