fix typo: "For completion" -> "For completeness"

[VladimirFokow]

Description

Please include a summary of the change and which issue is fixed. Please also include relevant motivation and context.
List any dependencies that are required for this change.

Fixes #302

Checklist

• I have run the pre-commit checks with ./orbit.sh --format
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• I have run all the tests with ./orbit.sh --test and they pass
• I have updated the changelog and the corresponding version in the extension's config/extension.toml file
• I have added my name to the CONTRIBUTORS.md or my name already exists there

[Mayankm96]

Thanks a lot for sending these MRs with doc fixes.

However, to avoid too many small/redundant "commits", we would prefer it you can send a single MR with all the docs fixes you have pointed out: #310, #311, #312, #313