Include varying positional param types in docs

src/lib.rs

@@ -515,7 +515,7 @@ impl Connection {
     /// ```rust,no_run
     /// # use rusqlite::{Connection};
     /// fn update_rows(conn: &Connection) {
-    ///     match conn.execute("UPDATE foo SET bar = 'baz' WHERE qux = ?", [1i32]) {
+    ///     match conn.execute("UPDATE foo SET bar = 'baz' WHERE qux = ?1 AND quux = ?2", params![1i32, 1.5f64]) {
     ///         Ok(updated) => println!("{} rows were updated", updated),
     ///         Err(err) => println!("update failed: {}", err),
     ///     }