patch 8.2.4474: memory allocation failures not tested in quickfix code

Problem:    Memory allocation failures not tested in quickfix code.
Solution:   Add alloc IDs and tests. (Yegappan Lakshmanan, closes #9848)

src/alloc.h

@@ -8,26 +8,37 @@
 
 /*
  * alloc.h: enumeration of alloc IDs.
+ * Used by test_alloc_fail() to test memory allocation failures.
  * Each entry must be on exactly one line, GetAllocId() depends on that.
  */
 typedef enum {
-	aid_none = 0,
-	aid_qf_dirname_start,
-	aid_qf_dirname_now,
-	aid_qf_namebuf,
-	aid_qf_module,
-	aid_qf_errmsg,
-	aid_qf_pattern,
-	aid_tagstack_items,
-	aid_tagstack_from,
-	aid_tagstack_details,
-	aid_sign_getdefined,
-	aid_sign_getplaced,
-	aid_sign_define_by_name,
-	aid_sign_getlist,
-	aid_sign_getplaced_dict,
-	aid_sign_getplaced_list,
-	aid_insert_sign,
-	aid_sign_getinfo,
-	aid_last
+    aid_none = 0,
+    aid_qf_dirname_start,
+    aid_qf_dirname_now,
+    aid_qf_namebuf,
+    aid_qf_module,
+    aid_qf_errmsg,
+    aid_qf_pattern,
+    aid_qf_efm_fmtstr,
+    aid_qf_efm_fmtpart,
+    aid_qf_title,
+    aid_qf_mef_name,
+    aid_qf_qfline,
+    aid_qf_qfinfo,
+    aid_qf_dirstack,
+    aid_qf_multiline_pfx,
+    aid_qf_makecmd,
+    aid_qf_linebuf,
+    aid_tagstack_items,
+    aid_tagstack_from,
+    aid_tagstack_details,
+    aid_sign_getdefined,
+    aid_sign_getplaced,
+    aid_sign_define_by_name,
+    aid_sign_getlist,
+    aid_sign_getplaced_dict,
+    aid_sign_getplaced_list,
+    aid_insert_sign,
+    aid_sign_getinfo,
+    aid_last
 } alloc_id_T;