Include ZWNJ in hashtags

[ahangarha]

In some RTL languages including Persian, ZWNJ character is used a lot and in particular, it is being used in hastags. For example in "#نیم‌فاصله" which has ZWNJ between نیم and فاصله.

This line of code needs to be updated and include ZWNJ in the hastag recognition pattern .

preprocessor/preprocessor/defines.py

Line 34 in 31d6850

HASHTAG_PATTERN = re.compile(r'#\w*')