add_irregular_rule: Add a custom rule for making "deregularizing" a word
Description
"regular" is the "deregularized" form of "irregular".
Calling plural("irregular") will return "regular" if you
define a rule such as add_irregular_rule("irregular", "regular").
Usage
add_irregular_rule(irregular_word, regular_word)
Arguments
irregular_word
the irregular form of the word
regular_word
regular form of a word
Value
nothing (function produces a side effect of modifying
in-memory internal package envrionment)