docs: fix grammar in tests/shanghai (#46)

Fix incomplete sentence in TestMultipleWithdrawalsSameAddress docstring.
The sentence "Test that multiple withdrawals can be sent to the same
address in." was missing proper structure. Rewrote following the pattern
used by TestUseValueInTx with self-contained summary and description.

Co-authored-by: Claude <noreply@anthropic.com>

Author: danceratopz

repo_subpaths_for_grammar_check.md

@@ -14,7 +14,7 @@ Status legend: `[ ]` pending, `[~]` in progress, `[x]` complete
 - [x] `tests/osaka/**/*.py` (~43 files)
 - [x] `tests/benchmark/**/*.py` (~36 files)
 - [x] `tests/json_infra/**/*.py` (~22 files)
-- [ ] `tests/shanghai/**/*.py` (~19 files)
+- [x] `tests/shanghai/**/*.py` (~19 files)
 - [ ] `tests/byzantium/**/*.py` (~11 files)
 - [ ] `tests/istanbul/**/*.py`, `berlin/**/*.py` (~18 files)
 - [ ] `tests/constantinople/**/*.py`, `amsterdam/**/*.py` (~16 files)

tests/shanghai/eip4895_withdrawals/test_withdrawals.py

@@ -300,11 +300,13 @@ def test_withdrawals_root(
 @pytest.mark.parametrize("test_case", ["single_block", "multiple_blocks"])
 class TestMultipleWithdrawalsSameAddress:
     """
-    Test that multiple withdrawals can be sent to the same address in.
+    Test that multiple withdrawals can be sent to the same address.
 
-    1. A single block.
+    1. `single_block`: Test multiple withdrawals to the same address in a
+    single block.
 
-    2. Multiple blocks.
+    2. `multiple_blocks`: Test multiple withdrawals to the same address across
+    multiple blocks.
     """
 
     @pytest.fixture