docs: fix in JSON example

Fix yet another syntax error in example.

Signed-off-by: Andrei Kartashev <a.kartashev@yadro.com>
Change-Id: I8be39bd31d4ed036905124bc6e18c52775592d97
diff --git a/docs/EntityManagerDbusAPI.md b/docs/EntityManagerDbusAPI.md
index a7ffabd..b4301a4 100644
--- a/docs/EntityManagerDbusAPI.md
+++ b/docs/EntityManagerDbusAPI.md
@@ -124,7 +124,7 @@
     {
         "name" : "front panel temp",
         "property": {
-            "key: {
+            "key": {
                 "key2": "value"
             }
         }