Merge pull request #8499 from swagger-api/annoying_spaces_fix

set pretty print option to remove extra spaces.

modules/swagger-codegen/src/main/java/io/swagger/codegen/v3/DefaultGenerator.java

@@ -1012,6 +1012,7 @@ private com.github.jknack.handlebars.Template getHandlebars(String templateFile)
             templateLoader = new ClassPathTemplateLoader("/" + templateDir, ".mustache");
         }
         final Handlebars handlebars = new Handlebars(templateLoader);
+        handlebars.prettyPrint(true);
         config.addHandlebarHelpers(handlebars);
         return handlebars.compile(templateFile);
     }