[PHP] Improve code style of generated code

Avoid trailing whitespace.

modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/PhpClientCodegen.java

@@ -167,6 +167,15 @@ public class PhpClientCodegen extends DefaultCodegen implements CodegenConfig {
                     .replaceAll(regLastPathSeparator+ "$", "");
     }
 
+    @Override
+    public String escapeText(String input) {
+        if (input != null) {
+            // Trim the string to avoid leading and trailing spaces.
+            return super.escapeText(input).trim();
+        }
+        return input;
+    }
+
     @Override
     public CodegenType getTag() {
         return CodegenType.CLIENT;