I might click on "new web browser", but would be less inclined to open a submission titled "new web browser written entirely in bash!".
By contrast, someone who is currently feverishly into learning shell programming might be more curious about "web browser written in bash" than about "new web browser'.
So mentioning bash is pertinent and useful.
From a different angle: if you're a hacker, it matters what something is written in. What something is written in is related to how that something works, and hackers care about how things work. (At least usually, when not wearing their "consumer of functionality through abstract interface" hat.)