docs: use american spelling of "organization"

[ghost]

Docs

Both spellings ("organisation" and "organization") are used throughout the page. This PR changes the British spelling of the term ("organisation") to the American spelling of the term ("organization") to make the language more consistent.

• Bugfix
• Feature
• Code style update
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other... Please describe:

PR checklist

Please check if your PR fulfills the following requirements:

• I have read the CONTRIBUTING.md doc
• The Git workflow follows our guidelines: CONTRIBUTING.md#git
• I have added necessary documentation (if appropriate)

What is the current behavior?

N/A, only docs changes. See description above.

Issue number: N/A

What is the new behavior?

Does this PR introduce a breaking change?

• Yes
• No

Other information

I've done my best to follow the contributing guidelines as written. Let me know if I've done something incorrectly :)