fix indentation and add braces

Objects/stringobject.c

@@ -3091,7 +3091,7 @@ string_expandtabs(PyStringObject *self, PyObject *args)
     i = 0; /* chars up to and including most recent \n or \r */
     j = 0; /* chars since most recent \n or \r (use in tab calculations) */
     e = PyString_AS_STRING(self) + PyString_GET_SIZE(self); /* end of input */
-    for (p = PyString_AS_STRING(self); p < e; p++)
+    for (p = PyString_AS_STRING(self); p < e; p++) {
         if (*p == '\t') {
             if (tabsize > 0) {
                 incr = tabsize - (j % tabsize);
@@ -3111,6 +3111,7 @@ string_expandtabs(PyStringObject *self, PyObject *args)
                 j = 0;
             }
         }
+    }
 
     if (i > PY_SSIZE_T_MAX - j)
         goto overflow1;