Sanitize characters not suitable for use with markup

[gmile]

A feature request, rather than an issue.

Can we have a sanitization of symbols, that are discouraged for use by the XML committee?

According to this document, specifically the "3. Characters not Suitable for use With Markup" section, there's a list of characters we could sanitize.

The need for this have risen after our users started to input control characters, randomly. A similar issue was found on StackOverflow.

[rgrove]

Seems like a good idea. This would probably be best implemented as a pre-parsing step.

I'm actually curious whether the Gumbo parser used in the dev-3.0.0 branch might already do some of this for us. Worth testing.