Include recommendation for escaping @id values

[balmas]

@balmas

... in this implementation sometimes properties use html-escaped versions of ids and paths and sometimes they don't.

@zflecth

I think my implementation uses escaped IDs when they're part of a path and unescaped IDs when they're just a normal string. So, urn:cts:greekLit:tlg0012.tlg001.perseus-grc2 is not escaped in the collections endpoint but it is escaped in the navigation endpoint because the ID is /navigation?.... I can't think of a better way of doing this, it seems wrong to escape a regular string and not escaping a path could cause problems.

Originally posted by @zfletch in #163 (comment)

[hcayless]

Recommend following RFC 3986 for identifier syntax in the documentation.

[jonathanrobie]

We may want to consider the following guidelines:

https://datatracker.ietf.org/doc/html/draft-ietf-iri-comparison-01