Call ctags on *.inc files as well

Call ctags on *.inc files as well

There are some *.inc already in the repository, mostly in demos/tests
and related to some algorithm implementations.  Introduction
of array_alloc.inc has made including these files in the tags generation
even more pertinent, so they are included now.

Also, this commit explicitly marks *.h files as containing C code,
overriding universal-ctags default of interpreting them as C++/ObjectiveC
ones.

Suggested-by: Neil Horman <nhorman@openssl.org>
Signed-off-by: Eugene Syromiatnikov <esyr@openssl.org>
Reviewed-by: Saša Nedvědický <sashan@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Paul Dale <ppzgs1@gmail.com>
Reviewed-by: Neil Horman <nhorman@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/28059)