r.cross: fix outdated doc (max 10 changed to 30 layers) (#3294)

raster/r.cross/r.cross.html

@@ -3,16 +3,12 @@ <h2>DESCRIPTION</h2>
 <em>r.cross</em> creates an <em>output</em> raster map layer representing
 all unique combinations of category values in the raster input layers
 (<b>input=</b><em>name,name,name</em>, ...).  At least two, but not more than
-ten, <em>input</em> map layers must be specified.  The user must also
+30, <em>input</em> map layers must be specified.  The user must also
 specify a name to be assigned to the <em>output</em> raster map layer
 created by <em>r.cross</em>.
 
 <h2>OPTIONS</h2>
 
-The program will be run non-interactively if the user specifies
-the names of between 2-10 raster map layers be used as <em>input</em>,
-and the name of a raster map layer to hold program <em>output</em>.
-
 <p>
 With the <b>-z</b> flag NULL values are not crossed.
 This means that if a NULL value occurs in any input data layer,