Only in verbose mode so as not to bloat struct symbol too much.

The key used is '/', just like in vi, less, etc.

More work is needed to allocate space on the symbol in a more clear way.

This experiment shows how to do it for the hist_browser, in the main
window.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Stephane Eranian <eranian@google.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>