added doc assert_eq to show what parse_with_params does
Just wanted this when i looked at the documentation.
@@ -277,6 +277,7 @@ impl Url {
/// # fn run() -> Result<(), ParseError> {
/// let url = Url::parse_with_params("https://example.net?dont=clobberme",
/// &[("lang", "rust"), ("browser", "servo")])?;
+ /// assert_eq!("https://example.net/?dont=clobberme&lang=rust&browser=servo", url.as_str());
/// # Ok(())
/// # }
/// # run().unwrap();
