sphinxdocs: close repo rule directives (#2892)

When converting the protos for repo rules to markdown, their blocks
weren't being
properly closed. To fix, just add the closing colons. Also added a test
of the text
generation.

sphinxdocs/private/proto_to_markdown.py

diff --git a/sphinxdocs/private/proto_to_markdown.py b/sphinxdocs/private/proto_to_markdown.py
index 9dac71d..58fb793 100644
--- a/sphinxdocs/private/proto_to_markdown.py
+++ b/sphinxdocs/private/proto_to_markdown.py
@@ -216,7 +216,9 @@
             self._render_attributes(repo_rule.attribute)
         if repo_rule.environ:
             self._write(":envvars: ", ", ".join(sorted(repo_rule.environ)))
-        self._write("\n")
+        self._write("\n\n")
+
+        self._write("::::::\n")
 
     def _render_rule(self, rule: stardoc_output_pb2.RuleInfo):
         rule_name = rule.rule_name

sphinxdocs/tests/proto_to_markdown/proto_to_markdown_test.py

diff --git a/sphinxdocs/tests/proto_to_markdown/proto_to_markdown_test.py b/sphinxdocs/tests/proto_to_markdown/proto_to_markdown_test.py
index 9d15b83..da6edb2 100644
--- a/sphinxdocs/tests/proto_to_markdown/proto_to_markdown_test.py
+++ b/sphinxdocs/tests/proto_to_markdown/proto_to_markdown_test.py
@@ -276,6 +276,41 @@
 """
         self.assertIn(expected, actual)
 
+    def test_render_repo_rule(self):
+        proto_text = """
+file: "@repo//pkg:foo.bzl"
+repository_rule_info: {
+  rule_name: "repository_rule",
+  doc_string: "REPOSITORY_RULE_DOC_STRING"
+  attribute: {
+    name: "repository_rule_attribute_a",
+    doc_string: "REPOSITORY_RULE_ATTRIBUTE_A_DOC_STRING"
+    type: BOOLEAN
+    default_value: "True"
+  }
+  environ: "ENV_VAR_A"
+}
+"""
+        actual = self._render(proto_text)
+        expected = """
+::::::{bzl:repo-rule} repository_rule(repository_rule_attribute_a=True)
+
+REPOSITORY_RULE_DOC_STRING
+
+:attr repository_rule_attribute_a:
+  {bzl:default-value}`True`
+  {type}`bool`
+  REPOSITORY_RULE_ATTRIBUTE_A_DOC_STRING
+  :::{bzl:attr-info} Info
+  :::
+
+
+:envvars: ENV_VAR_A
+
+::::::
+"""
+        self.assertIn(expected, actual)
+
 
 if __name__ == "__main__":
     absltest.main()