message: docs(cache): update doc strings
diff: @@ -55,7 +55,7 @@ class Strategy: # pylint: disable=too-few-public-methods
  Strategies can be configured in `superset/config.py`:
  - CELERYBEAT_SCHEDULE = {
  + beat_schedule = {
  'cache-warmup-hourly': {
  'task': 'cache-warmup',
  'schedule': crontab(minute=1, hour='*'), # @hourly
  @@ -82,7 +82,7 @@ class DummyStrategy(Strategy): # pylint: disable=too-few-public-methods
  This is a dummy strategy that will fetch all charts. Can be configured by:
  - CELERYBEAT_SCHEDULE = {
  + beat_schedule = {
  'cache-warmup-hourly': {
  'task': 'cache-warmup',
  'schedule': crontab(minute=1, hour='*'), # @hourly
  @@ -105,7 +105,7 @@ class TopNDashboardsStrategy(Strategy): # pylint: disable=too-few-public-method
  """
  Warm up charts in the top-n dashboards.
  - CELERYBEAT_SCHEDULE = {
  + beat_schedule = {
  'cache-warmup-hourly': {
  'task': 'cache-warmup',
  'schedule': crontab(minute=1, hour='*'), # @hourly
  @@ -151,7 +151,7 @@ class DashboardTagsStrategy(Strategy): # pylint: disable=too-few-public-methods
  """
  Warm up charts in dashboards with custom tags.
  - CELERYBEAT_SCHEDULE = {
  + beat_schedule = {
  'cache-warmup-hourly': {
  'task': 'cache-warmup',
  'schedule': crontab(minute=1, hour='*'), # @hourly
  