feat: Allow clashing types ref (controlled via Reflector.NamesWithPkg option)

[candiduslynx]

No description provided.

[candiduslynx]

@samlown this just allows the schema to use advanced names.
Additionally, the pkg path is escaped to be a valid JSON pointer.

I've successfully tested (via https://pkg.go.dev/github.com/santhosh-tekuri/jsonschema/v5) the resulting schema for testdata.Odd with the following input:

{
  "dummy1": {"A":"str"},
  "dummy2": {"B":12345}
}

An alternative to this could be replacing all / & ~ symbols with underscores or defined char, but it'll be prone to clash in the following case:

root
⌞_ pkg
   ⌞_ another_pkg
⌞_ pkg_another
   ⌞_ pkg

P.S.: using . instead of / & ~ might just work, though

[candiduslynx]

@samlown I propose reviewing this one before #106, as this will make the diff for #106 much shorter & easier to review

[candiduslynx]

Replaced by #109