[status-] decrease latency of status() when other threads run

Inspect is slow to look up context lines, so stack(0) is
a bit faster. See https://stackoverflow.com/a/17407257
When other busy threads run, stack() can have high latency,
more than 100ms. stack(0) has much less latency in that
situation.

visidata/features/status_source.py

@@ -5,7 +5,7 @@
 
 @VisiData.api
 def getStatusSource(vd):
- stack = inspect.stack()
+ stack = inspect.stack(0) #2370
  for i, sf in enumerate(stack):
  if sf.function in 'status aside'.split():
  if stack[i+1].function in 'error fail warning debug'.split():