typo fixed in indexing.rst (pandas-dev#46130)

fixed p.loc['a', : , :]  to p.loc['a', : ] 
Issue: pandas-dev#46125

doc/source/user_guide/indexing.rst

@@ -89,7 +89,7 @@ Getting values from an object with multi-axes selection uses the following
 notation (using ``.loc`` as an example, but the following applies to ``.iloc`` as
 well). Any of the axes accessors may be the null slice ``:``. Axes left out of
 the specification are assumed to be ``:``, e.g. ``p.loc['a']`` is equivalent to
-``p.loc['a', :, :]``.
+``p.loc['a', :]``.
 
 .. csv-table::
     :header: "Object Type", "Indexers"