Rollup merge of #59037 - Manishearth:intra-doc-false, r=QuietMisdreavus
Rollup merge of #59037 - Manishearth:intra-doc-false, r=QuietMisdreavus

Avoid some common false positives in intra doc link checking

The empty string case is never going to be a link. The numeric case may be a link, but if it were it would have resolved locally. It's more likely the makeshift markdown footnote notation (`[0]`, etc)

r? @QuietMisdreavus

graydon/rust,graydon/rust,graydon/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,aidancully/rust,aidancully/rust,aidancully/rust