perf tools: Fix duplicated words in documentation and comments

perf tools: Fix duplicated words in documentation and comments

- "the the"
- "in in"
- "a a"

Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Markus Heidelberg <m.heidelberg@cab.de>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>