Rule with superfluous separator accepted in strict mode (`Mo-Fr: 12:00`)

[westnordost]

The readme states:

In non-strict mode the following further differences are allowed: [...]

• superfluous ":" after weekday range

However, Mo-Fr: 12:00 is parsed without error also in strict mode.

[simonpoole]

The comment in the source is

// spec is not clear on this, however ":" is used in real life here a lot

as a tendency I wouldn't change the behaviour as it may simply be a question of this being missed when the specification was created.