Update src/librustc_error_codes/error_codes/E0628.md

Co-Authored-By: Dylan DPC <dylan.dpc@gmail.com>

Author: ayushmishra2005

src/librustc_error_codes/error_codes/E0628.md

@@ -15,7 +15,7 @@ fn main() {
 ```
 
 At present, it is not permitted to pass more than one explicit
-parameter for a generator.This can be fixed by using only
+parameter for a generator.This can be fixed by using
 0 or 1 parameter for generator. So, for example, we might resolve
 the previous example by passing only one parameter.