bpo-32758: Warn that ast.parse() and ast.literal_eval() can segfault …

…the interpreter (pythonGH-5960)

(cherry picked from commit 7a7f100)

Co-authored-by: Brett Cannon <brettcannon@users.noreply.github.com>

Doc/library/ast.rst

@@ -113,6 +113,11 @@ and classes for traversing abstract syntax trees:
    Parse the source into an AST node.  Equivalent to ``compile(source,
    filename, mode, ast.PyCF_ONLY_AST)``.
 
+   .. warning::
+      It is possible to crash the Python interpreter with a
+      sufficiently large/complex string due to stack depth limitations
+      in Python's AST compiler.
+
 
 .. function:: literal_eval(node_or_string)
 
@@ -126,6 +131,11 @@ and classes for traversing abstract syntax trees:
    capable of evaluating arbitrarily complex expressions, for example involving
    operators or indexing.
 
+   .. warning::
+      It is possible to crash the Python interpreter with a
+      sufficiently large/complex string due to stack depth limitations
+      in Python's AST compiler.
+
    .. versionchanged:: 3.2
       Now allows bytes and set literals.