Mark a function as deprecated and trigger an error.
The current behavior is to trigger a user error if WP_DEBUG is true.
This function is to be used in every function that is deprecated.
Adapted from Easy Digital Downloads (https://github.com/easydigitaldownloads/Easy-Digital-Downloads)
||The function that was called|
||The version of Simmer that deprecated the function|
||Optional. The function that should have been called|