message: Update ag_logging.py with clarity and reference
  * fixes typo
  * adds clarity to text
  * adds reference to absl's logging doc page
  ref
diff: @@ -46,7 +46,7 @@ def set_verbosity(level, alsologtostdout=False):
  More verbose logging is useful to enable when filing bug reports or doing
  more in-depth debugging.
  - There are two controls that control the logging verbosity:
  + There are two parameters that control the logging verbosity:
  * The `set_verbosity` function
  @@ -70,7 +70,8 @@ def set_verbosity(level, alsologtostdout=False):
  # No effect, because set_verbosity was already called.
  ```
  - Logs entries are output to [absl](https://abseil.io)'s default output,
  + Logs entries are output to [absl](https://abseil.io)'s
  + [default output](https://abseil.io/docs/python/guides/logging),
  with `INFO` level.
  Logs can be mirrored to stdout by using the `alsologtostdout` argument.
  Mirroring is enabled by default when Python runs in interactive mode.
  @@ -78,7 +79,7 @@ def set_verbosity(level, alsologtostdout=False):
  Args:
  level: int, the verbosity level; larger values specify increased verbosity;
  0 means no logging. When reporting bugs, it is recommended to set this
  - value to a larges number, like 10.
  + value to a larger number, like 10.
  alsologtostdout: bool, whether to also output log messages to `sys.stdout`.
  """
  global verbosity_level
  