ignore trailing whitespace on URL arg

src/args.rs

@@ -169,7 +169,7 @@ pub fn parse<T: AsRef<str>>(args: &[T]) -> Result<Config, ArgError> {
                     return Err(ArgError::new(format!("unknown argument: {}", arg)));
                 } else {
                     got_url = true;
-                    cfg.start = arg.into();
+                    cfg.start = arg.trim().into();
                 }
             }
         }
@@ -200,6 +200,12 @@ mod tests {
         assert_eq!(cfg.wide, false);
     }
 
+    #[test]
+    fn test_ignore_trailing_whitespace() {
+        let cfg = parse(&["some-url.io   "]).expect("should work");
+        assert_eq!(cfg.start, "some-url.io");
+    }
+
     #[test]
     fn test_unknown() {
         let err = parse(&["-z"]).expect_err("-z shouldn't exist");