XMLBear.py: Add CAN_FIX metadata
XMLBear.py: Add CAN_FIX metadata

XMLBear can apply patches to formatting errors.
So, setting the CAN_FIX value to ``formatting``.

Closes https://github.com/coala/coala-bears/issues/2420

coala-analyzer/coala-bears,coala/coala-bears,coala/coala-bears,refeed/coala-bears,refeed/coala-bears,refeed/coala-bears,coala-analyzer/coala-bears,refeed/coala-bears,coala-analyzer/coala-bears,coala/coala-bears,refeed/coala-bears,coala/coala-bears,coala/coala-bears,coala/coala-bears,coala/coala-bears,refeed/coala-bears,coala-analyzer/coala-bears,coala-analyzer/coala-bears,refeed/coala-bears,refeed/coala-bears,coala-analyzer/coala-bears,coala/coala-bears,refeed/coala-bears,refeed/coala-bears,coala-analyzer/coala-bears,refeed/coala-bears,coala/coala-bears,coala/coala-bears,coala-analyzer/coala-bears,coala/coala-bears,coala/coala-bears,coala-analyzer/coala-bears