Merge bitcoin/bitcoin#33546: test: add functional test for TestShell (matching doc example)

57f7c68821 test: add functional test for `TestShell` (matching doc example) (Sebastian Falbesoner)
53874f7934 doc: test: update TestShell example instructions/options (Sebastian Falbesoner)

Pull request description:

  This PR adds a functional framework test for the `TestShell` class. The primary motivation for this is to avoid that the example instructions for the interactive Python shell in `test-shell.md` get outdated or broken without noticing, a problem we had already several times in the past (see #26520, #27906, #31415). Having a copy is still not perfect, as docs and functional test have to be kept in sync, but I don't expect this to be a problem in practice, assuming the hint in the functional test comment is hopefully noticed if changes are made.

  Alternatively, the example instructions in `test-shell.md` could be removed with a hint to the functional test (I tend to prefer to keep the docs as-is though, showing the full REPL interaction).

  The first commit contain two small removal fix-ups in `test-shell.md` regarding the result of the `createwallet` RPC call and the mentioning of the `noshutdown` option that was removed earlier (see #31620). Could be backported to v30.

ACKs for top commit:
  brunoerg:
    ACK 57f7c68821
  stratospher:
    ACK 57f7c68.
  pinheadmz:
    ACK 57f7c68821

Tree-SHA512: 25c35af46b742bbefce7838708437529bbf613fa3d1f0fba590cacef0acdde82b3a78c7a01459c73eaac26ce3f1041e54092d098f0fc94a8c76ac0b4f4970338

test/functional/test_runner.py

@@ -362,6 +362,7 @@ BASE_SCRIPTS = [
     'rpc_getdescriptorinfo.py',
     'rpc_mempool_info.py',
     'rpc_help.py',
+    'feature_framework_testshell.py',
     'tool_rpcauth.py',
     'p2p_handshake.py',
     'p2p_handshake.py --v2transport',