Loss of information strategy stopwords vs window

[scossin]

These two matching strategies lead to a similar output:

1. Stopwords strategy

matcher = Matcher.build(
    keywords=["cancer prostate"],
    stopwords=["de", "la"],
    w=1
)
annots = matcher.annot_text(text="cancer de la prostate")
for annot in annots:
    print(annot)
    # cancer prostate	0 6;13 21	cancer prostate

2. Window strategy

matcher = Matcher.build(
    keywords=["cancer prostate"],
    w=3
)
annots = matcher.annot_text(text="cancer de la prostate")
for annot in annots:
    print(annot)
    # cancer prostate	0 6;13 21	cancer prostate

It can be useful to keep the information if stopwords were used in the matching strategy.
Also in 1) the words are discontinuous although the annotation can be considered as continuous, the human annotator would annotate this way: cancer de la prostate 0 21 cancer prostate.
When generating the Brat format, it's important to have the choice to include or not the stopwords.