perf ui browser annotate: Show in the title the source code view toggle

perf ui browser annotate: Show in the title the source code view toggle

Ingo reported that having a visual cue if the source code view is
enabled will help in noticing a bug when no source is presented.

Change the title scnprintf routine for the annotation browser to do
that.

More work is needed to have the capabilities of the existing
disassemblers listed somehow and start using the fastest one but switch
to another that provides features only made available by some particular
one, like the first one, the objdump output parsing one.

Suggested-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Ingo Molnar <mingo@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/Z_TYux5fUg2pW-pF@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>