Allow more flexible names for the special + files

[MorganConrad]

Perhaps this has already been discussed - apologies if so, but my github search skills are limited, and I didn't see this is the discussions, though 6169 is close.

In addition to +page.svelte, +page.js, etc..., could SvelteKit also recognize file patterns such as +XXX.page.js, +YYY.layout.svelte, etc? That way a programmer could provide a clearer name, probably related to the route, and avoid having a dozen tabs open all named the same. I like the folder based routing, it's very logical and consistent, nor do I mind the leading +. But all the tabs of the same name is a pain point for many programmers. (Yes, we should limit how many tabs are open, and eat our vegetables)

e.g. a programmer might prefer names like +help.page.svelte, +blog.slug.page.js

Thanks for a great project!