Add missing comma in docs

Found by Michael Voznesensky <voznesenskym@gmail.com>

Signed-off-by: Doug Davis <dug@us.ibm.com>

docs/sources/reference/api/docker_remote_api_v1.15.md

@@ -124,7 +124,7 @@ Create a container
              "Cmd":[
                      "date"
              ],
-             "Entrypoint": ""
+             "Entrypoint": "",
              "Image":"base",
              "Volumes":{
                      "/tmp": {}

docs/sources/reference/api/docker_remote_api_v1.16.md

@@ -124,7 +124,7 @@ Create a container
              "Cmd":[
                      "date"
              ],
-             "Entrypoint": ""
+             "Entrypoint": "",
              "Image":"base",
              "Volumes":{
                      "/tmp": {}