Update generic-views.md

Small grammar changes.
Argh! Style! :)

A couple of issues: 

1. "May override..." vs "May be overridden..." — only one of those. 
2. Commas, and sub-sentential clauses. 

The older I get the less I lean towards lots of 2 — it ends up reading like Proust. General queries: are these clauses really _sub-sentential_; do the commas really make it clearer?

In want of an official _Style Guide_ we could merge all number of these. @tomchristie do you have any thoughts? (Otherwise, Why Not?™)

// @lnhubbell — Thanks for the PR — I'm not criticising in this comment — just raising the question before merging.