[3.13] gh-131094: Refine math.isclose docs (GH-131139) (#131392)

gh-131094: Refine `math.isclose` docs (GH-131139)
(cherry picked from commit 3f50f96)

Co-authored-by: Guy Jacoby <[email protected]>

Author: miss-islington

Doc/library/math.rst

@@ -350,8 +350,8 @@ Floating point manipulation functions
 
    *abs_tol* is the absolute tolerance; it defaults to ``0.0`` and it must be
    nonnegative.  When comparing ``x`` to ``0.0``, ``isclose(x, 0)`` is computed
-   as ``abs(x) <= rel_tol  * abs(x)``, which is ``False`` for any ``x`` and
-   rel_tol less than ``1.0``.  So add an appropriate positive abs_tol argument
+   as ``abs(x) <= rel_tol  * abs(x)``, which is ``False`` for any nonzero ``x`` and
+   *rel_tol* less than ``1.0``.  So add an appropriate positive *abs_tol* argument
    to the call.
 
    The IEEE 754 special values of ``NaN``, ``inf``, and ``-inf`` will be