The code intended to show the user 'Potential Matches' when the entry
is not found on Webster's dictionary. The feature is valuable since it
guides the user to the nearest valid words. Still, there is a
mistake in the condition that prevents it to be met at the right
moments. Fix the condition to let the add-on notify users of the
suggested words.

DRY rule says, "Don't repeat yourself." The code will be easier to
read if we develop every logic once and then reuse it.

There are many words in Merriam Webster’s dictionary that derive from
other words but do not include a definition. Webster calls these
words Undefined Run-Ons (UROs). Despite lack of definition, it has
specified part-of-speech for all, and stated pronunciation and
phonetic transcription for considerable numbers of them.

To cover also adding pronunciation and phonetic transcription of
undefined words, we should look for them at URO (Undefined Run-On)
tag of the related entries. This requires us to include potential
entries in our search criteria in due time and expand procedures of
adding vocal pronunciation and phonetic transcription.

To reduce complexity, clean coders prefer modular structure. Refactor
_get_definition() while keeping the solution approach as same as
possible.

Resolves: z1lc#27