[php-maint] Bug#766816: link aliases in manual

[積丹尼 Dan Jacobson]

Package: php-doc
Version: 20140201-1

On e.g., /usr/share/doc/php-doc/html/ref.datetime.html
and /usr/share/doc/php-doc/html/function.date-format.html etc. hundreds
of places,

where it says Alias of DateTime::setISODate etc.
Alias of DateTime::...
This function is an alias of: DateTime::...

they should all be links, so the user can get to what the thing being
talked about it one click!