Add Spector tests for 'fragment' style

[antkmsft]

A question on https://github.com/microsoft/typespec/tree/main/packages/http-specs/specs/routes :
I don't see any tests for 'fragment' style ('#' delimiter?). If that style is not deprecated, could they get added? Not sure how to implement this, specifically what is expected when explode=true. A test would clarify that. Currently, we have to throw if we see 'fragment' because we aren't sure if the code we'd emit is correct, and we'd prefer not to add such code that is not covered by tests.

[timotheeguerin]

the reason is while uri template and typespec does support it I believe fragment are not to be sent to the server and are a client only piece of the uri.
So it could have some use if one used typespec to represent some client side only routing(like could imagine some SPA) I am not sure its worth documenting this as working for a client -> server interaction.