Update docs/src/autodiff/operator_overloading.md

Author: oxinabox

docs/src/autodiff/operator_overloading.md

@@ -7,7 +7,7 @@ an overload of an AD system's overloaded type.
 For example, using the signature type `Tuple{typeof(+), Real, Real}` to make 
 `+(::DualNumber, ::DualNumber)` call the `frule` for `+`.
 A signature type tuple always has the form:
-`Tuple{typeof(operation), typeof{pos_arg1}, typeof{pos_arg2...}}`, where `pos_arg1` is the
+`Tuple{typeof(operation), typeof{pos_arg1}, typeof{pos_arg2}, ...}`, where `pos_arg1` is the
 first positional argument.
 One can dispatch on the signature type to make rules with argument types your AD does not support not call `eval`;
 or more simply you can just use conditions for this.