Fix docs after split from bazel_tools

The `*_java_repository` macros no longer register toolchains.

toolchains/local_java_repository.bzl

diff --git a/toolchains/local_java_repository.bzl b/toolchains/local_java_repository.bzl
index ab25f0d..54d9baa 100644
--- a/toolchains/local_java_repository.bzl
+++ b/toolchains/local_java_repository.bzl
@@ -261,7 +261,10 @@
 )
 
 def local_java_repository(name, java_home = "", version = "", build_file = None, build_file_content = None, **kwargs):
-    """Registers a runtime toolchain for local JDK and creates an unregistered compile toolchain.
+    """Defines runtime and compile toolchains for a local JDK.
+
+    Register the toolchains defined by this macro via `register_toolchains("@<name>//:all")`, where
+    `<name>` is the value of the `name` parameter.
 
     Toolchain resolution is constrained with --java_runtime_version flag
     having value of the "name" or "version" parameter.

toolchains/remote_java_repository.bzl

diff --git a/toolchains/remote_java_repository.bzl b/toolchains/remote_java_repository.bzl
index cbd8b13..2fa7a36 100644
--- a/toolchains/remote_java_repository.bzl
+++ b/toolchains/remote_java_repository.bzl
@@ -33,7 +33,10 @@
 )
 
 def remote_java_repository(name, version, target_compatible_with = None, prefix = "remotejdk", **kwargs):
-    """Imports and registers a JDK from a http archive.
+    """Imports a JDK from a http archive and creates runtime toolchain definitions for it.
+
+    Register the toolchains defined by this macro via `register_toolchains("@<name>//:all")`, where
+    `<name>` is the value of the `name` parameter.
 
     Toolchain resolution is determined with target_compatible_with
     parameter and constrained with --java_runtime_version flag either having value