Add missing Starlark files to “all_rules” targets. (bazel-contrib#2434)

This is important for Stardoc, which insists on knowing about all transitively
loaded Starlark files.

go/BUILD.bazel

@@ -12,7 +12,11 @@ filegroup(
 
 filegroup(
     name = "all_rules",
-    srcs = glob(["*.bzl"]) + ["//go/private:all_rules"],
+    srcs = glob(["*.bzl"]) + [
+        "//go/platform:all_rules",
+        "//go/private:all_rules",
+        "//go/toolchain:all_rules",
+    ],
     visibility = ["//visibility:public"],
 )
 

go/platform/BUILD.bazel

@@ -11,6 +11,12 @@ package(default_visibility = ["//visibility:public"])
 
 declare_config_settings()
 
+filegroup(
+    name = "all_rules",
+    srcs = glob(["*.bzl"]),
+    visibility = ["//visibility:public"],
+)
+
 filegroup(
     name = "all_files",
     testonly = True,

go/toolchain/BUILD.bazel

@@ -7,6 +7,12 @@ package(default_visibility = ["//visibility:public"])
 
 declare_constraints()
 
+filegroup(
+    name = "all_rules",
+    srcs = glob(["*.bzl"]),
+    visibility = ["//visibility:public"],
+)
+
 filegroup(
     name = "all_files",
     testonly = True,