Fix a duplicate ref name in docs.
Fix a duplicate ref name in docs.

elacuesta/scrapy,starrify/scrapy,pablohoffman/scrapy,eLRuLL/scrapy,scrapy/scrapy,pawelmhm/scrapy,pablohoffman/scrapy,dangra/scrapy,elacuesta/scrapy,starrify/scrapy,scrapy/scrapy,eLRuLL/scrapy,eLRuLL/scrapy,elacuesta/scrapy,dangra/scrapy,scrapy/scrapy,dangra/scrapy,starrify/scrapy,pablohoffman/scrapy,pawelmhm/scrapy,pawelmhm/scrapy