Use Typographically Correct Spacing

Instead of the regular space `' '` (U+0020) between the numeric value and the unit, a [narrow no-break space should be used](https://en.wikipedia.org/wiki/Non-breaking_space#Width_variation) `' '` (U+202F).

This obviously does not always make a difference in appearance, e.g. when being used on the REPL with a fixed-size font, but sometimes it does and especially for correct copy-pase behavior.

Start by locating the formatting path that places a space between a numeric value and its unit, then inspect any existing tests for rendered quantities. Update the relevant output behavior to use U+202F and verify that the resulting text preserves the intended narrow non-breaking spacing and copy-paste behavior.

Written by the indexing model from the issue text.