061322 fix php typo (#826)

Author: Chris Cho

source/php.txt

@@ -143,7 +143,7 @@ instance instead of a PHP integer type.
 MongoDB Compatibility
 ~~~~~~~~~~~~~~~~~~~~~
 
-The following compatibility table specifies the recommended version(s) of the Mongo Scala driver for use with a specific version of MongoDB.
+The following compatibility table specifies the recommended version(s) of the PHP driver for use with a specific version of MongoDB.
 
 The first column lists the driver version(s).