Thanks for bringing this to my attention. We're actually in the middle of a documentation audit this week, and this is exactly the type of issue we want to flag.
Toolchain tutorial contradicts ToolchainInfo reference documentation
### Description of the problem / feature request:

Reference documentation:
https://docs.bazel.build/versions/master/skylark/lib/platform_common.html#ToolchainInfo
> The provider constructor for ToolchainInfo. The constructor takes the type of the toolchain, and a map of the toolchain's data.

Tutorial:
https://docs.bazel.build/versions/master/toolchains.html#creating-a-toolchain-rule
```
def _my_toolchain_impl(ctx):
  toolchain = platform_common.ToolchainInfo(
    compiler = ctx.attr.compiler,
    system_lib = ctx.attr.system_lib,
    arch_flags = ctx.attr.arch_flags,
  )
  return [toolchain]
```

The tutorial doesn't call `ToolchainInfo` with the type of the toolchain at all, and doesn't pass in a map, just keyword arguments. I think the tutorial documents the correct usage.

src/main/java/com/google/devtools/build/lib/skylarkbuildapi/platform/ToolchainInfoApi.java
src/main/java/com/google/devtools/build/lib/skylarkbuildapi/platform/ToolchainInfoApi.java
diff --git a/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/platform/ToolchainInfoApi.java b/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/platform/ToolchainInfoApi.java
index ab37760d34563f..868c2801950cfa 100644
--- a/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/platform/ToolchainInfoApi.java
+++ b/src/main/java/com/google/devtools/build/lib/skylarkbuildapi/platform/ToolchainInfoApi.java
@@ -18,13 +18,12 @@
 import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkModuleCategory;
 
-/**
- * Info object representing data about a specific toolchain.
- */
+/** Info object representing data about a specific toolchain. */
 @SkylarkModule(
     name = "ToolchainInfo",
-    doc = "Provides access to data about a specific toolchain.",
-    category = SkylarkModuleCategory.PROVIDER
-)
-public interface ToolchainInfoApi extends StructApi {
-}
+    doc =
+        "Provider which allows rule-specific toolchains to communicate data back to the actual"
+            + " rule implementation. Read more about <a"
+            + " href='../../toolchains.$DOC_EXT'>toolchains</a> for more information.",
+    category = SkylarkModuleCategory.PROVIDER)
+public interface ToolchainInfoApi extends StructApi {}
