document `get_result` multi row result case
`get_result` returns only/always the first result - even if the query
returns x-rows.
@@ -1200,6 +1200,9 @@ pub trait RunQueryDsl<Conn>: Sized {
/// it will implicitly add a `RETURNING *` to the query,
/// unless a returning clause was already specified.
///
+ /// This method only returns the first row that was affected, even if more
+ /// rows are affected.
+ ///
/// # Example
///
/// ```rust
