Use camelCase for extension URL

Author: alexlipovka

input/fsh/structure-definition-enable-chart.fsh

@@ -1,12 +1,11 @@
 Extension: EnableChart
-Id: enable-chart
+Id: enableChart
 Title: "Enable Chart"
 Description: "Enable chart extension"
-* ^url = "https://emr-core.beda.software/StructureDefinition/enable-chart"
 * extension contains
-    link-id-x 1..1 and
-    link-id-y 1..1
-* extension[link-id-x].value[x] only string
-* extension[link-id-x] ^short = "Link ID for the X-axis"
-* extension[link-id-y].value[x] only string
-* extension[link-id-y] ^short = "Link ID for the Y-axis"
+    linkIdX 1..1 and
+    linkIdY 1..1
+* extension[linkIdX].value[x] only string
+* extension[linkIdX] ^short = "Link ID for the X-axis"
+* extension[linkIdY].value[x] only string
+* extension[linkIdY] ^short = "Link ID for the Y-axis"