https://superuser.com/review/suggested-edits/756623 refers to 'Accent colors', but this ought be 'Theme colors'.
As a general concept, editing other people's posts is meant as a tool to help improve them without significantly changing their content - e.g., fixing typos, improving grammar, improving markdown formatting, etc.
In this edit, you changed the content of the answer, as @Run5k noted in his rejection message. A better approach would be to leave a comment and note the mistake in the post. The post's author could then either correct the post, or explain why he or she disagree with you. And, of course, if you think an answer is wrong, you could always downvote it to reflect that.
- I have no idea whether this answer is in fact wrong or not - I'm referring to the way SE communities work, not to the specifics details about MS-Word, which I do not use).
- I did not review this edit. The users who did review it (bertieb who approved it and Toto and Run5k who rejected it) may have more specific feedback.