Eliminate duplicated words (for docs)

What does this MR do?

Eliminates duplicated words only in the docs.

What are the relevant issue numbers?

part of #54230 (closed)

Relates !23184 (merged) (for apps and tests)

Does this MR meet the acceptance criteria?

• [n/a] Changelog entry added, if necessary
• Documentation created/updated
• [n/a] Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• [n/a] Conforms to the database guides
• [n/a] Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.