include method to remove stopwords

[mynameisvinn]

included method to remove stopwords from text.

here is an example with the blob text:

>>> blob = TextBlob(text)
>>> blob.remove_stopwords

... should produce the following output

'\nThe titular threat of The Blob has always struck me as the ultimate movie\n
monster: an insatiably hungry, amoeba-like mass able to penetrate\n
virtually any safeguard, capable of--as a doomed doctor chillingly\n
describes it--"assimilating flesh on contact.\n
Snide comparisons to gelatin be damned, it\'s a concept with the most\n
devastating of potential consequences, not unlike the grey goo scenario\n
proposed by technological theorists fearful of\n
artificial intelligence run rampant.\n'

[JiwaniZakir]

The @cached_property decorator in blob.py is incompatible with the fname parameter on remove_stopwords — cached properties are accessed as attributes (e.g., blob.remove_stopwords), not called as methods, so the fname argument can never actually be passed by a caller and the default "stopwords.txt" is baked in permanently. The relative path "stopwords.txt" will also raise a FileNotFoundError for any caller whose working directory isn't the project root; it should resolve to an absolute path using os.path.join(os.path.dirname(__file__), ...) or leverage NLTK's built-in nltk.corpus.stopwords, which TextBlob already depends on. Additionally, the return type is a plain str rather than a TextBlob instance, which breaks method chaining and is inconsistent with the rest of the API (e.g., words returns a WordList). The method name itself should be a noun (e.g., clean_text or filtered_words) to match the property convention used throughout the class.