Clean up linter statements around cli conditions

[nikosbosse]

As suggested by Hugo, we should clean the linter statements surrounding cli.

The syntax to disable a specific linter is quite fussy and requires a period at the end. The current comment disables all linter.
The simplest option is probably to follow what this linter is suggesting in all cases:

      #nolint start: keyword_quote_linter
      cli_abort(
        c(
          `!` = "If a column 'scale' is present, entries with scale =='natural'
          are required for the transformation."
        )
      )

Originally posted by @Bisaloo in #791 (comment)