Added a new property Description from Description2

[bertrandgorge]

Hello,

This is a little attempt at adding a new extra property for the description of the page, as computed by the extension Description2.

I was not sure about the unit test so there's some work on that remaining. Appart from that it seems to work as intended.

I let you decide if you think it is worthy adding !

[krabina]

Did you also test what happens if the Description2 extension is not installed?

[bertrandgorge]

Hello @krabina yes there's no hard dependency on the Description2 extension as it only looks for the presence of the Parser property "description" (see

SemanticExtraSpecialProperties/src/PropertyAnnotators/PageDescriptionPropertyAnnotator.php

Line 71 in bda9d9b

if ( $description !== false ) { // set by Description2 extension, install it if you want proper og:description support

)

NB : for the moment I won't personaly be using this code, so there's no pressing at merging anything. It's just there if someone finds it useful enough ?