The tab and indentation settings in Text Editor > Behavior are only used
for non-code files. Add a hint with links to the respective coding style
settings.

Change-Id: I1d7c1154269c4914d511ef6ef3308a2b1f933d52
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@digia.com>
Reviewed-by: David Schulz <david.schulz@digia.com>