Tips (for reviewers) php-xml doesn't provides xml extension

[Remi Collet]

During a recent package review a notice this (very old) singularity

pci (from php-pear-PHP-CompatInfo) could reports the need for the xml
extension (often because of utf8_encode / utf8_decode functions)

XML is a buildtin extension, so provided by php-common

	$ php -n -m | grep -i xml
	libxml
	SimpleXML
	xml

The php-xml sub-package provides some additional XML related extensions
	dom
	wddx
	xmlreader
	xmlwriter
	xsl


So, a lot of package (web apps) are probably requiring php-xml when it
is not really needed.

Just a notice,
I don't think we have to fix this.

Remi.