Remove sort/1 and group/1

Reserve these for sorting with jq-coded comparators.

builtin.c

@@ -951,17 +951,12 @@ static const char* const jq_builtins[] = {
   "def break: error(\"break\");",
   "def map(f): [.[] | f];",
   "def select(f): if f then . else empty end;",
-  "def sort(f): _sort_by_impl(map([f]));",
-  "def sort_by(f): sort(f);",
-  "def group(f): _group_by_impl(map([f]));",
-  "def group_by(f): group(f);",
-  "def unique: group(.) | map(.[0]);",
-  "def unique(f): group(f) | map(.[0]);",
-  "def unique_by(f): unique(f);",
-  "def max(f): _max_by_impl(map([f]));",
-  "def min(f): _min_by_impl(map([f]));",
-  "def max_by(f): max(f);",
-  "def min_by(f): min(f);",
+  "def sort_by(f): _sort_by_impl(map([f]));",
+  "def group_by(f): _group_by_impl(map([f]));",
+  "def unique: group_by(.) | map(.[0]);",
+  "def unique_by(f): group_by(f) | map(.[0]);",
+  "def max_by(f): _max_by_impl(map([f]));",
+  "def min_by(f): _min_by_impl(map([f]));",
 #include "libm.h"
   "def add: reduce .[] as $x (null; . + $x);",
   "def del(f): delpaths([path(f)]);",