Singularization of words ending in "series" was incorrect due to the special case for "series" itself, this included some reasonably commonly used words:
>> "series".singularize => "series" (correct)
>> "nurseries".singularize => "nurseries" (incorrect)
>> "miseries".singularize => "miseries" (incorrect)
The patch makes the original singular rule more specific to "series" itself which lets words like "miseries" and "nurseries" fall back to existing rules that work for them.
Note: Pluralization is not affected as the original rule is singular only.
Note: The inclusion of logic for hyphenated words ending in "series" may be too specific for a general patch, however without it this patch would have broken existing code which relied on singularization for things like "mini-series" so I have included it as it does not add any additional inflector rules.
