Indexing index pages is harmless, and also "nofollow" is appropriate for
public lists with lots of junk, advertising etc. We have nearly zero
spam, so following links in posts is fine.
This covers all of the html files in mailman's template directory, and
we should have a consistent look for all pages. (Including archived
messages.) Also tweak the front page to have a link to the mailman
"listinfo" page with the complete list of the hosted mailing lists.
Ie, the difference between using it as a language and as a module is now
the same in both. Also, improve `scribble/html' (and
`scribble/html/htmllang') by reproviding most of the corresponding text
modules.
Change `meta/web' accordingly, and improve code by making a new langugae
(`#lang meta/web'). This language is similar to `scribble/html' except
that it uses the plain scribble reader (not the `-inside' one), it
doesn't use the customized module-begin feature (that uses
`output-xml'), and it adds all the relevant bits of `meta/web/common'.
(Also, "meta/web/common.rkt" is gone, since it's used only as a language
now.)
This commit has lots of details and binding games, so it's tricky, and
potentially caused some problems. (Took me a while to track many
breakages, so I won't be surprised if there are more.)
