docs(manual): Bump url and rules to high status

A.k.a. "Good maturity"
The main concern here is that some constructs previously used
an hbox, and could not span multiples lines.
They now use "liners" supporting this use case.
Other refactors also made the code much better.

documentation/c05-packages.sil

@@ -117,7 +117,7 @@ This section covers a range of different topics from initial capitals to text tr
 \package-documentation{unichar}
 
 \subsection{url}
-\status:medium
+\status:high
 \package-documentation{url}
 
 \subsection{gutenberg}
@@ -146,7 +146,7 @@ Line-filling patterns or rules, rectangular blobs of inks... What else to say?
 \package-documentation{leaders}
 
 \subsection{rules}
-\status:medium
+\status:high
 \package-documentation{rules}
 
 \section{Boxes & Effects}