Issue #5067: improve some json error messages.
Patch by Serhiy Storchaka.
diff --git a/Doc/library/json.rst b/Doc/library/json.rst
index 2bdc577..8686561 100644
--- a/Doc/library/json.rst
+++ b/Doc/library/json.rst
@@ -99,7 +99,7 @@
         "json": "obj"
     }
     $ echo '{1.2:3.4}' | python -mjson.tool
-    Expecting property name: line 1 column 1 (char 1)
+    Expecting property name enclosed in double quotes: line 1 column 1 (char 1)
 
 .. highlight:: python3