perf python: Fix spelling mistake "metics" -> "metrics"

There is a spelling mistake in a Python doc string. Fix it.

Fixes: d0550be70f7ab84d ("perf python: Add parse_metrics function")
Reviewed-by: Ian Rogers <[e-mail]>
Signed-off-by: Colin Ian King <[e-mail]>
Cc: Adrian Hunter <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Ian Rogers <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Kan Liang <[e-mail]>
Cc: [e-mail]
Cc: Mark Rutland <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/python.c

···
 		.ml_meth  = (PyCFunction) pyrf__parse_metrics,
 		.ml_flags = METH_VARARGS,
 		.ml_doc	  = PyDoc_STR(
-			"Parse a string of metics or metric groups and return an evlist.")
+			"Parse a string of metrics or metric groups and return an evlist.")
 	},
 	{
 		.ml_name  = "pmus",