Exclude node_modules dir from kotlin-stdlib-js project

Minor: shorter IdeaModel configuration.

libraries/stdlib/js/build.gradle

@@ -5,6 +5,7 @@ plugins {
 description = 'Kotlin Standard Library for JS'
 
 apply plugin: 'kotlin2js'
+apply plugin: 'idea'
 
 configurePublishing(project)
 
@@ -60,6 +61,12 @@ dependencies {
     merger project(":tools:kotlin-stdlib-js-merger")
 }
 
+idea {
+    module {
+        excludeDirs = files('node_modules').toSet()
+    }
+}
+
 createPreprocessorTask(project, "Main", "${projectDir}/../src/kotlin", commonSrcDir)
 createPreprocessorTask(project, "Test", "${projectDir}/../test", commonTestSrcDir)