make getDisplayName() abstract so its implementation cannot be forgotten

add getDisplayName() to "String literal concatenation missing whitespace" inspection

plugins/InspectionGadgets/src/com/siyeh/ig/BaseInspection.java

@@ -61,6 +61,11 @@ public abstract class BaseInspection extends BaseJavaLocalInspectionTool {
     return m_shortName;
   }
 
+  @Nls
+  @NotNull
+  @Override
+  public abstract String getDisplayName();
+
   @Override
   @Nls
   @NotNull

plugins/InspectionGadgets/src/com/siyeh/ig/bugs/StringConcatenationMissingWhitespaceInspection.java

@@ -22,6 +22,7 @@ import com.siyeh.InspectionGadgetsBundle;
 import com.siyeh.ig.BaseInspection;
 import com.siyeh.ig.BaseInspectionVisitor;
 import com.siyeh.ig.psiutils.ParenthesesUtils;
+import org.jetbrains.annotations.Nls;
 import org.jetbrains.annotations.NotNull;
 
 import javax.swing.*;
@@ -34,6 +35,13 @@ public class StringConcatenationMissingWhitespaceInspection extends BaseInspecti
   @SuppressWarnings("PublicField")
   public boolean ignoreNonStringLiterals = false;
 
+  @Nls
+  @NotNull
+  @Override
+  public String getDisplayName() {
+    return InspectionGadgetsBundle.message("string.concatenation.missing.whitespace.display.name");
+  }
+
   @NotNull
   @Override
   protected String buildErrorString(Object... infos) {