Make KDoc generate documentation on red code

KDoc is not a compiler, so it should not care whether or not the code is valid.
Therefore suppress the compiler's exit code, errors and warnings in KDoc plugin

libraries/tools/kdoc/src/main/kotlin/org/jetbrains/kotlin/doc/KDocCompiler.kt

@@ -6,6 +6,7 @@ import org.jetbrains.jet.cli.common.CLIConfigurationKeys
 import org.jetbrains.jet.cli.common.arguments.K2JVMCompilerArguments;
 import org.jetbrains.jet.cli.jvm.K2JVMCompiler
 import org.jetbrains.jet.config.CompilerConfiguration
+import org.jetbrains.jet.cli.common.messages.MessageCollector
 
 /**
 * Main for running the KDocCompiler
@@ -23,6 +24,9 @@ class KDocCompiler() : K2JVMCompiler() {
     protected override fun configureEnvironment(configuration : CompilerConfiguration, arguments : K2JVMCompilerArguments) {
         super.configureEnvironment(configuration, arguments)
         configuration.add(CLIConfigurationKeys.COMPILER_PLUGINS, KDoc(arguments as KDocArguments))
+
+        // Suppress all messages from the compiler, because KDoc is not a compiler
+        configuration.put(CLIConfigurationKeys.MESSAGE_COLLECTOR_KEY, MessageCollector.NONE)
     }
 
     protected override fun createArguments() : K2JVMCompilerArguments {