Handle receiving no exception to an error listener correctly

[51-code]

Describe the bug

From investigating the root cause of #13, it was noticed that the RecognitionException given as a parameter in an ErrorListener might be null in some cases:
RecognitionExceptions docs: "It is null in the case where the parser was able to recover in line without exiting the surrounding rule."

Expected behavior

Should be recognized and logged properly.

How to reproduce

E.g. the query || has this behavior.

Screenshots

Software version

pth_03 version: 5.11.0

Desktop (please complete the following information if relevant):

• OS:
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Additional context

The NullPointerException that resulted from this is handled in #13, but the fix is rather superficial. It should be investigated if this specific case requires some other response than the usual syntax error.