IDEA-187747 Suggest Collectors.joining() collector for String stream

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/completion/normal/AllCollectors.java

@@ -2,6 +2,6 @@ import java.util.*;
 
 class Foo {
   void m() {
-    Arrays.asList("a", "b").stream().colle<caret>
+    Arrays.asList(1, 2).stream().colle<caret>
   }
 }

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/completion/normal/AllCollectors_after.java

@@ -3,6 +3,6 @@ import java.util.stream.Collectors;
 
 class Foo {
   void m() {
-    Arrays.asList("a", "b").stream().collect(Collectors.toCollection(<caret>))
+    Arrays.asList(1, 2).stream().collect(Collectors.toCollection(<caret>))
   }
 }

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/completion/normal/CollectorsJoining.java

@@ -0,0 +1,7 @@
+import java.util.*;
+
+class Foo {
+  void m() {
+    Arrays.asList("a", "b").stream().join<caret>
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/completion/normal/CollectorsJoiningInsideCollect.java

@@ -0,0 +1,7 @@
+import java.util.*;
+
+class Foo {
+  void m() {
+    String l = Arrays.asList("a", "b").stream().collect(joi<caret>)
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/completion/normal/CollectorsJoiningInsideCollect_after.java

@@ -0,0 +1,8 @@
+import java.util.*;
+import java.util.stream.Collectors;
+
+class Foo {
+  void m() {
+    String l = Arrays.asList("a", "b").stream().collect(Collectors.joining(<caret>))
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/completion/normal/CollectorsJoining_after.java

@@ -0,0 +1,8 @@
+import java.util.*;
+import java.util.stream.Collectors;
+
+class Foo {
+  void m() {
+    Arrays.asList("a", "b").stream().collect(Collectors.joining(<caret>))
+  }
+}