Fix Sphinx formatting in release notes

GitOrigin-RevId: 7d5315fc4c4836dbc51e471f2544e8cdec452405
diff --git a/docs/ReleaseNotes.rst b/docs/ReleaseNotes.rst
index 5e6be24..5ca1e1e 100644
--- a/docs/ReleaseNotes.rst
+++ b/docs/ReleaseNotes.rst
@@ -184,11 +184,11 @@
 --------------------
 
 - The ``_ExtInt(N)`` extension has been standardized in C23 as ``_BitInt(N)``.
-The mangling of this type in C++ has accordingly changed: under the Microsoft
-ABI it is now mangled using the ``_BitInt`` spelling, and under the Itanium ABI
-it is now mangled using a dedicated production. Note: the ABI for ``_BitInt(N)``
-is still in the process of being stabilized, so this type should not yet be
-used in interfaces that require ABI stability.
+  The mangling of this type in C++ has accordingly changed: under the Microsoft
+  ABI it is now mangled using the ``_BitInt`` spelling, and under the Itanium ABI
+  it is now mangled using a dedicated production. Note: the ABI for ``_BitInt(N)``
+  is still in the process of being stabilized, so this type should not yet be
+  used in interfaces that require ABI stability.
 
 OpenMP Support in Clang
 -----------------------