patch 8.2.3320: some local functions are not static

Problem:    Some local functions are not static.
Solution:   Add "static".  Move snprintf() related code to strings.c.
            (Yegappan Lakshmanan, closes #8734)

src/vim9type.c

@@ -24,7 +24,7 @@
  * Allocate memory for a type_T and add the pointer to type_gap, so that it can
  * be easily freed later.
  */
-    type_T *
+    static type_T *
 get_type_ptr(garray_T *type_gap)
 {
     type_T *type;