Remove redundant null guard in classification message loop

[evansantos]

Context

GitSniff PR #10 finding (ℹ️ Info): Minor code cleanup.

Problem

In src/index.ts, the loop over recentHistory had a redundant if (!msg) continue check. history.slice(-3) always returns defined elements.

Note: This was already fixed as part of the warnings fix commit. Closing.

Ref: PR #10 GitSniff review

[evansantos]

Already fixed in the warnings fix commit (removed the redundant null guard).