Make StaticString conform to Hashable

[DevAndArtist (Adrian Meister)]

Slightly off-topic, but I‘d love to see mutating methods eventually added to StaticString. You should be able to combine multiple different StaticString‘s to a new StaticString.

Should we add more mutating methods to `StaticString`?

I'm currently playing around with a custom Swift wrapper around the logging API from os.activity module and I'm hitting two issues related to StaticString. For security reasons the os.activity API can only accept static strings which limits its functionality. Now I would like to create an activity that print's the owning type and some methods that are called on the instance to create a deep nested structure. The following image is just an example what I want to achieve at some point: [Activit…