bug#44834: Fix for failing indentation of Tcl procs nested in namespace

[Eli Zaretskii]

> From: Richard Stallman <rms@gnu.org>
> Cc: eliz@gnu.org, anticrisisg@gmail.com, 44834@debbugs.gnu.org,
>       dgutov@yandex.ru
> Date: Thu, 11 Feb 2021 08:39:24 -0500
> 
>   > I don't quite understand what you mean by "if a line contains a symbol".
>   > Do you mean that strings or comments don't count?
> 
> No.  I meant to say that even one symbol on a line maks it nontrivial.
> But you're right that strings and comments count.  So do numbers.

Empty lines are clearly trivial, but what other examples of trivial
lines exist?  Should we say "non-empty lines"?