[3.12] gh-125761: Clarify repeated warning suppression criteria in warnings module (gh-126331)

(cherry picked from commit 10eeec2)

Co-authored-by: 고병찬 <[email protected]>

Author: miss-islington

Doc/library/warnings.rst

@@ -178,6 +178,19 @@ If a warning is reported and doesn't match any registered filter then the
 "default" action is applied (hence its name).
 
 
+
+.. _repeated-warning-suppression-criteria:
+
+Repeated Warning Suppression Criteria
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The filters that suppress repeated warnings apply the following criteria to determine if a warning is considered a repeat:
+
+- ``"default"``: A warning is considered a repeat only if the (*message*, *category*, *module*, *lineno*) are all the same.
+- ``"module"``: A warning is considered a repeat if the (*message*, *category*, *module*) are the same, ignoring the line number.
+- ``"once"``: A warning is considered a repeat if the (*message*, *category*) are the same, ignoring the module and line number.
+
+
 .. _describing-warning-filters:
 
 Describing Warning Filters