improve wording in settings

src/main/java/org/jastadd/tooling/RelAstGrammarFileType.java

@@ -23,7 +23,7 @@ public class RelAstGrammarFileType extends LanguageFileType {
   @NotNull
   @Override
   public String getDescription() {
-    return "Relational RAG grammar specification.";
+    return "Relational RAG Grammar";
   }
 
   @NotNull