pad: adjust language

Signed-off-by: Peter Gadfort <[email protected]>

Author: gadfort

src/pad/README.md

@@ -412,7 +412,7 @@ rdl_route
 
 ### Selectively routing terminals
 
-If some of of the terminals in the design do not need to be RDL routed, this can be done by assigning `RDL_ROUTE` to a terminal.
+If some of of the terminals in the design do not need to be RDL routed, this can be done by assigning `RDL_ROUTE 0` to a terminal.
 
 ```tcl
 # Assumes iterm is the pin to be not be routed