Stle changes to SWC website

[OscarSiba]

How could the content be improved?

Software Carpentry: https://swc-new-website.netlify.app/about-us/

• [x] Please retitle this to be "About us". Please compare to same page on LC and DC sites.
• [x] Please also add the "Subscribe to our newsletter" button here.
• [x] In the second paragraph, please hyperlink "Having started in 1998" to this link: https://carp-new-website.netlify.app/about-us/#our-history
• [x] In the second paragraph, please write the number "100,000" as part of the bit that says "almost one hundred thousand people".
• [x] The very last sentence reads 'please see “Software Carpentry: Lessons Learned”'. Please revise this to say: "please read Software Carpentry: Lessons Learned."

Software Carpentry Lessons: https://swc-new-website.netlify.app/lessons/

In the introductory paragraph:

• [x] Please spell instructor and instructors with a capital "I".
• [x] Please spell organization and visualization with "s" instead of "z".

Software Carpentry Curriculum Advisors: https://swc-new-website.netlify.app/about-us/curriculum-advisors/

• [x] Please separate the last sentence from the rest, and skip a line, so that it stands out.

[OscarSiba]

Tagging you here @maneesha as I can't seem to be able to assign the issue to you.

[maneesha]

Addressed with #53