fix: Render xref in name element similar to everywhere else

When `xref` is in `title`, if `xref` has a target to a `reference` use
square brackets (`[ <target text> ]`).
If the `xref` target is not a reference don't use brackets or parenthesis.

If `xref` element has text content:
For `reference` targets:
    `<text content> [<target>]`
For other targets:
    `<text content> (<target>)`

xml2rfc/writers/html.py

@@ -2847,8 +2847,16 @@ def render_xref(self, h, x):
                 if format == 'none':
                     reftext = content
                     hh = build.span(reftext, classes='xref cite')
+                elif target in self.refname_mapping and format != 'title':
+                    if content:
+                        hh = build.span(content, ' ', '[', reftext, ']', classes='xref cite')
+                    else:
+                        hh = build.span('[', reftext, ']', classes='xref cite')
                 else:
-                    hh = build.span('[', reftext, ']', classes='xref cite')
+                    if content:
+                        hh = build.span(content, ' ', '(', reftext, ')', classes='xref cite')
+                    else:
+                        hh = build.span(reftext, classes='xref cite')
             else:
                 srefclass = 'xref internal'
                 if not content and format != 'title':