SAP: rename module to "Network streams (SAP)"

Fixes: Qt playlist was not able to display the SAP service discovery
because Qt relies on a call to playlist_ChildSearchName().
The name defined as module longtext must be the same as the SD probe
name.

modules/services_discovery/sap.c

@@ -118,7 +118,7 @@ VLC_SD_PROBE_HELPER("sap", N_("Network streams (SAP)"))
 
 vlc_module_begin ()
     set_shortname( N_("SAP"))
-    set_description( N_("SAP Announcements") )
+    set_description( N_("Network streams (SAP)") )
     set_category( CAT_PLAYLIST )
     set_subcategory( SUBCAT_PLAYLIST_SD )