Reapply "[ruby/uri] Warn compatibility methods in RFC3986_PARSER"
This reverts commit 3da7e440e9fca835f5475a98f1c0afb4d2ac71db.
Reapply "[ruby/uri] Warn compatibility methods in RFC3986_PARSER"
This reverts commit 3da7e440e9fca835f5475a98f1c0afb4d2ac71db.