fix(docs): split code block to fix blacken-docs parse error in spec

Signed-off-by: Sébastien Han <seb@redhat.com>

Author: leseb

docs/superpowers/specs/2026-05-18-alembic-migrations-design.md

@@ -146,16 +146,20 @@ VECTOR_STORE_FILE_BATCHES_SCHEMA = { ... }
 
 Service files change their `create_table()` calls to import from `schema.py`:
 
+Before (inline schema):
+
 ```python
-# Before (inline schema):
 await self.sql_store.create_table("prompts", {
     "id": ColumnDefinition(type=ColumnType.STRING, primary_key=True),
     "prompt_id": ColumnType.STRING,
-    ...
 })
+```
+
+After (imported schema):
 
-# After (imported schema):
+```python
 from ogx.core.storage.schema import PROMPTS_SCHEMA
+
 await self.sql_store.create_table(TABLE_PROMPTS, PROMPTS_SCHEMA)
 ```