Add missing toolsnap

Author: RossTarrant

pkg/github/__toolsnaps__/update_issue_body.snap

@@ -8,7 +8,7 @@
   "inputSchema": {
     "properties": {
       "body": {
-        "description": "The new body content for the issue",
+        "description": "Issue body; Markdown supported.",
         "type": "string"
       },
       "issue_number": {