drop the stupid extra &pop in the response callback

bip-XXXX.mediawiki

@@ -83,7 +83,7 @@ I.e. amount=50.00 or amount=50 is treated as 50 BTC, and amount=50,000.00 is inv
 
 The URI MAY include a "pop" (or "req-pop") parameter who's value can be used to build a URI which the wallet application can, after payment completes, "open" to provide proof the payment was completed or other information about the payment.
 
-The value of a "pop" (or "req-pop") parameter shall be a percent-encoded (per RFC 3986 section 2.1) URI prefix. The wallet application, if it supports providing payment information SHOULD first percent-decode the provided URI once, append "&pop=" followed by the Payment Information to the resulting URI and open it with the default system handler for the given URI.
+The value of a "pop" (or "req-pop") parameter shall be a percent-encoded (per RFC 3986 section 2.1) URI prefix. The wallet application, if it supports providing payment information SHOULD percent-decode the provided URI once then append the Payment Information to the resulting URI and open it with the default system handler for the given URI.
 
 A wallet MUST validate that the provided URI's scheme is not (case-insensitive) "http", "https", "file", "javascript", "mailto" or any other scheme which will open in a web browser prior to opening it.