Fix typo in example `default_java_toolchain`
The example `default_java_toolchain has the line
```
java_runtime = "@bazel_tools///tools/jdk:remote_jdk11"
```
which contains a third extra `/` in `@bazel_tools///`, and instead should be
```
java_runtime = "@bazel_tools//tools/jdk:remote_jdk11
```
Closes
@@ -250,7 +250,7 @@ default_java_toolchain(
name = "repository_default_toolchain",
configuration = DEFAULT_TOOLCHAIN_CONFIGURATION, # One of predefined configurations
# Other parameters are from java_toolchain rule:
- java_runtime = "@bazel_tools///tools/jdk:remote_jdk11", # JDK to use for compilation and toolchain's tools execution
+ java_runtime = "@bazel_tools//tools/jdk:remote_jdk11", # JDK to use for compilation and toolchain's tools execution
jvm_opts = BASE_JDK9_JVM_OPTS + ["--enable_preview"], # Additional JDK options
javacopts = DEFAULT_JAVACOPTS + ["--enable_preview"], # Additional javac options
source_version = "9",
