Please include hint in HTML output that text version has no maximum report size

This bug was originally reported by Holger Levsen (holger@debian.org) in Debian bug #944882:

Package: diffoscope
Version: 1.30
Severity: minor

Dear diffoscope maintainers,

(some aspects of) the current behavior of diffoscope and 'max report size' 
is as:

- only considered for html output, but not for text (where it is unlimited),
  default is 400kb max.

I'd like to suggest:

- increase the default max to 1024kb or maybe 2mb? (actually, why not
  more? why a limited default?)
- include a hint in the html output that the text output is not limited
  in size. (if html hits the max. not sure if once or at every truncated
  occasion.)


Thanks for your considerations & all the shiny code!

--=20
cheers,
	Holger