Add a description of the internal array data structure.

src/types.c

@@ -0,0 +1,13 @@
+#include "types.h"
+
+libab_result libab_array_init(libab_array* array) {
+    return libab_ref_vec_init(&array->elems);
+}
+
+libab_result libab_array_insert(libab_array* array, libab_ref* value) {
+    return libab_ref_vec_insert(&array->elems, value);
+}
+
+void libab_array_free(libab_array* array) {
+    libab_ref_vec_free(&array->elems);
+}