bpo-40045: Make "dunder" method documentation easier to locate (#19153)

* issue 40045

* Update lexical_analysis.rst

Make "dunder" method documentation easier(GH-19153)

Co-authored-by: Joannah Nanjekye <33177550+nanjekyejoannah@users.noreply.github.com>

Author: j0m0k0

Doc/reference/lexical_analysis.rst

@@ -376,11 +376,11 @@ characters:
       information on this convention.
 
 ``__*__``
-   System-defined names. These names are defined by the interpreter and its
-   implementation (including the standard library).  Current system names are
-   discussed in the :ref:`specialnames` section and elsewhere.  More will likely
-   be defined in future versions of Python.  *Any* use of ``__*__`` names, in
-   any context, that does not follow explicitly documented use, is subject to
+   System-defined names, informally known as "dunder" names. These names are
+   defined by the interpreter and its implementation (including the standard library).
+   Current system names are discussed in the :ref:`specialnames` section and elsewhere.
+   More will likely be defined in future versions of Python.  *Any* use of ``__*__`` names,
+   in any context, that does not follow explicitly documented use, is subject to
    breakage without warning.
 
 ``__*``