Use Typographically Correct Spacing

[PatrickHaecker]

Instead of the regular space ' ' (U+0020) between the numeric value and the unit, a narrow no-break space should be used ' ' (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.