[doc] Clarify the nature of the root logger in the logging documentation (GH-119440)

Co-authored-by: Vinay Sajip <[email protected]>

Author: jkunimune

Doc/library/logging.rst

@@ -109,11 +109,11 @@ The ``name`` is potentially a period-separated hierarchical value, like
 Loggers that are further down in the hierarchical list are children of loggers
 higher up in the list.  For example, given a logger with a name of ``foo``,
 loggers with names of ``foo.bar``, ``foo.bar.baz``, and ``foo.bam`` are all
-descendants of ``foo``.  The logger name hierarchy is analogous to the Python
-package hierarchy, and identical to it if you organise your loggers on a
-per-module basis using the recommended construction
-``logging.getLogger(__name__)``.  That's because in a module, ``__name__``
-is the module's name in the Python package namespace.
+descendants of ``foo``.  In addition, all loggers are descendants of the root
+logger. The logger name hierarchy is analogous to the Python package hierarchy,
+and identical to it if you organise your loggers on a per-module basis using
+the recommended construction ``logging.getLogger(__name__)``.  That's because
+in a module, ``__name__`` is the module's name in the Python package namespace.
 
 
 .. class:: Logger
@@ -1157,10 +1157,12 @@ functions.
 
 .. function:: getLogger(name=None)
 
-   Return a logger with the specified name or, if name is ``None``, return a
-   logger which is the root logger of the hierarchy. If specified, the name is
-   typically a dot-separated hierarchical name like *'a'*, *'a.b'* or *'a.b.c.d'*.
-   Choice of these names is entirely up to the developer who is using logging.
+   Return a logger with the specified name or, if name is ``None``, return the
+   root logger of the hierarchy. If specified, the name is typically a
+   dot-separated hierarchical name like *'a'*, *'a.b'* or *'a.b.c.d'*. Choice
+   of these names is entirely up to the developer who is using logging, though
+   it is recommended that ``__name__`` be used unless you have a specific
+   reason for not doing that, as mentioned in :ref:`logger`.
 
    All calls to this function with a given name return the same logger instance.
    This means that logger instances never need to be passed between different parts