sqlite-utils create-table docs, plus doc unit test

Refs #27. Closes #108

tests/test_docs.py

@@ -0,0 +1,22 @@
+from sqlite_utils import cli
+from pathlib import Path
+import pytest
+import re
+
+docs_path = Path(__file__).parent.parent / "docs"
+commands_re = re.compile(r"(?:\$ |    )sqlite-utils (\S+) ")
+
+
+@pytest.fixture(scope="session")
+def documented_commands():
+    rst = (docs_path / "cli.rst").read_text()
+    return {
+        command
+        for command in commands_re.findall(rst)
+        if "." not in command and ":" not in command
+    }
+
+
+@pytest.mark.parametrize("command", cli.cli.commands.keys())
+def test_plugin_hooks_are_documented(documented_commands, command):
+    assert command in documented_commands