Set up docs

BUILD.bazel

@@ -9,7 +9,7 @@ bzl_library(
 
 exports_files(
     ["bazel_env.bzl"],
-    visibility = ["//visibility:public"],
+    visibility = ["//docs:__pkg__"],
 )
 
 exports_files(

bazel_env.bzl

@@ -331,7 +331,7 @@ _bazel_env_rule = rule(
     executable = True,
 )
 
-def bazel_env(name, *, tools = {}, toolchains = {}, tags = [], visibility = ["//visibility:private"]):
+def bazel_env(name, *, tools = {}, toolchains = {}, **kwargs):
     # type: (string, dict[string, string | Label], dict[string, string | Label]) -> None
     tool_targets = []
     toolchain_targets = []
@@ -400,6 +400,5 @@ def bazel_env(name, *, tools = {}, toolchains = {}, tags = [], visibility = ["//
         unique_name_tool = unique_name_tool,
         tool_targets = tool_targets,
         toolchain_targets = toolchain_targets,
-        tags = tags,
-        visibility = visibility,
+        **kwargs,
     )

docs/BUILD.bazel

@@ -1,3 +1,4 @@
+load("@bazel_skylib//rules:diff_test.bzl", "diff_test")
 load("@rules_proto//proto:proto_lang_toolchain.bzl", "proto_lang_toolchain")
 load("@stardoc//stardoc:stardoc.bzl", "stardoc")
 
@@ -8,6 +9,22 @@ stardoc(
     deps = ["//:bazel_env"],
 )
 
+diff_test(
+    name = "bazel_env_test",
+    failure_message = "Please run:\n    bazel run //docs:update",
+    file1 = "bazel_env.md",
+    file2 = "//docs-gen:bazel_env.md",
+)
+
+sh_binary(
+    name = "update",
+    srcs = ["update.sh"],
+    data = [
+        ":bazel_env",
+    ],
+)
+
+# Precompiled proto toolchain for stardoc
 proto_lang_toolchain(
     name = "protoc_java_toolchain",
     command_line = "--java_out=$(OUT)",