For new checks and feature suggestions

• https://www.shellcheck.net/ (i.e. the latest commit) currently gives no useful warnings about this
• I searched through https://github.com/koalaman/shellcheck/issues and didn't find anything related

Here's a snippet or screenshot that shows a potential problem:

I've been using unshare in my script's shebangs to sandbox them; however, doing so prevents shellcheck from knowing what shell is being used. For example:

#!/usr/bin/env -S unshare --mount --map-root-user /bin/sh
[...]

Here's what shellcheck currently says:

SC1008 (error): This shebang was unrecognized. [...]

Here's what I wanted to see:

It'd be handy if shellcheck could handle unshare inside env -S lines somehow (if reasonable to implement). Alternatively, using --shell or # shellcheck shell=sh solves this issue manually.