CLJS-3471: fix printing of negative zero

Author: borkdude

src/main/cljs/cljs/core.cljs

@@ -10470,6 +10470,7 @@ reduces them without incurring seq initialization"
             (js/isNaN obj) "##NaN"
             (identical? obj js/Number.POSITIVE_INFINITY) "##Inf"
             (identical? obj js/Number.NEGATIVE_INFINITY) "##-Inf"
+            (js/Object.is obj -0.0) "-0.0"
             :else (str_ obj)))
 
         (object? obj)

src/test/cljs/cljs/printing_test.cljs

@@ -74,6 +74,7 @@
     (is (= (pr-str 1) "1"))
     (is (= (pr-str -1) "-1"))
     (is (= (pr-str -1.5) "-1.5"))
+    (is (= (pr-str -0.0) "-0.0"))
     (is (= (pr-str [3 4]) "[3 4]"))
     (is (= (pr-str "foo") "\"foo\""))
     (is (= (pr-str :hello) ":hello"))