suggestion(path): introduce delimiter.ts files

[iuioiua]

path/mod.ts exports a delimiter variable.
https://github.com/denoland/deno_std/blob/bd08c2b57d37f6443aa5f6a58dc5b3f5e981effc/path/mod.ts#L48-L50

This should be moved to a separate path/delimiter.ts file with a similar structure to path/separator.ts. path/mod.ts should then re-export from that path/delimiter.ts file.

[joehillen]

@iuioiua Can you add more details?

[iuioiua]

Sorry. See above.

[iuioiua]

Update: instead, let's introduce constants.ts files containing separators and delimiters.