Should a grammatical article be a part of a web link anchor

When hyperlinking a noun in a webpage (or in an application), which is a part of a longer text/sentence, should a grammatical article (such as "a" in English) be a part of a link anchor text?

I.e., which of the following is correct from a point of view of native English speaker?

A cat is a mammal.

A cat is a mammal.

I'm not sure if this may vary with a language. In my native language, there are no articles. It may actually be a trivial question for native English speaker.