Docs: properly link to main page of docs.

book/src/lints.md

diff --git a/book/src/lints.md b/book/src/lints.md
index e408c44..8943274 100644
--- a/book/src/lints.md
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 This chapter provides details about the different lint categories, which kind
 of lints they offer, and recommended actions when you should see a lint out of
 that category. For examples, see the [Clippy lint documentation] and filter by
-category. For an overview of these categories, see the [introduction](..).
+category. For an overview of these categories, see the
+[introduction](index.md).
 
 The different lint groups were defined in the [Clippy 1.0 RFC].