CodeMirror: Multiplexing Parser Demo

## Multiplexing Parser Demo

<html> <body style="<<magic>>"> <h1><< this is not <html >></h1> << multiline not html at all : &amp; <link/> >> <p>this is html again</p> </body> </html>

Demonstration of a multiplexing mode, which, at certain boundary strings, switches to one or more inner modes. The out (HTML) mode does not get fed the content of the `<< >>` blocks. See the manual and the source for more information.

Parsing/Highlighting Tests: normal, verbose.