Systematic spellcheck in CI

[alexpyattaev]

Problem

• Fixing spelling in comments one PR at a time is grossly inefficient
• Context: https://discord.com/channels/428295358100013066/560496939779620864/1404536581209194536

Proposed Solution

• We need an automated way to check spelling in comments and, where possible/appropriate, enforce it.

[akhi3030]

FWIW: In a previous project, we ended up using https://github.com/near/nearcore/blob/2d5945ac5b70bc9e61d8cc7b90d01bb2cdbd5fe6/.github/workflows/ci.yml#L228.