Fixed sphinx warnings:
```
whatsnew/3.11.rst:1674: WARNING: 'opcode' reference target not found: BEFORE_WITH [ref.opcode]
whatsnew/3.4.rst:1982: WARNING: 'opcode' reference target not found: LOAD_CLASSDEREF [ref.opcode]
whatsnew/3.6.rst:2369: WARNING: 'opcode' reference target not found: FORMAT_VALUE [ref.opcode]
whatsnew/3.6.rst:2374: WARNING: 'opcode' reference target not found: BUILD_CONST_KEY_MAP [ref.opcode]
whatsnew/3.6.rst:2378: WARNING: 'opcode' reference target not found: CALL_FUNCTION [ref.opcode]
whatsnew/3.6.rst:2378: WARNING: 'opcode' reference target not found: CALL_FUNCTION_KW [ref.opcode]
whatsnew/3.6.rst:2378: WARNING: 'opcode' reference target not found: BUILD_MAP_UNPACK_WITH_CALL [ref.opcode]
whatsnew/3.6.rst:2378: WARNING: 'opcode' reference target not found: BUILD_TUPLE_UNPACK_WITH_CALL [ref.opcode]
whatsnew/3.6.rst:2389: WARNING: 'opcode' reference target not found: STORE_ANNOTATION [ref.opcode]
whatsnew/3.7.rst:2479: WARNING: 'opcode' reference target not found: CALL_METHOD [ref.opcode]
whatsnew/3.7.rst:2482: WARNING: 'opcode' reference target not found: STORE_ANNOTATION [ref.opcode]
whatsnew/3.8.rst:2155: WARNING: 'opcode' reference target not found: BREAK_LOOP [ref.opcode]
whatsnew/3.8.rst:2155: WARNING: 'opcode' reference target not found: CONTINUE_LOOP [ref.opcode]
whatsnew/3.8.rst:2155: WARNING: 'opcode' reference target not found: SETUP_LOOP [ref.opcode]
whatsnew/3.8.rst:2155: WARNING: 'opcode' reference target not found: SETUP_EXCEPT [ref.opcode]
whatsnew/3.8.rst:2155: WARNING: 'opcode' reference target not found: ROT_FOUR [ref.opcode]
whatsnew/3.8.rst:2155: WARNING: 'opcode' reference target not found: BEGIN_FINALLY [ref.opcode]
whatsnew/3.8.rst:2155: WARNING: 'opcode' reference target not found: CALL_FINALLY [ref.opcode]
whatsnew/3.8.rst:2155: WARNING: 'opcode' reference target not found: POP_FINALLY [ref.opcode]
whatsnew/3.8.rst:2155: WARNING: 'opcode' reference target not found: END_FINALLY [ref.opcode]
whatsnew/3.8.rst:2155: WARNING: 'opcode' reference target not found: WITH_CLEANUP_START [ref.opcode]
whatsnew/3.9.rst:1206: WARNING: 'opcode' reference target not found: LOAD_ASSERTION_ERROR [ref.opcode]
```