Add expression functions with context boundaries

tools/vscode-gotlin/snippets/gotlin.code-snippets

@@ -8,6 +8,16 @@
     ],
     "description": "Gotlin function"
   },
+  "Expression Function": {
+    "prefix": "exprfun",
+    "body": ["fun ${1:name}(${2}) = ${3:expression}"],
+    "description": "Gotlin expression-bodied function"
+  },
+  "With Go Context": {
+    "prefix": "withcontext",
+    "body": ["withContext(${1:request}.context()) {", "    $0", "}"],
+    "description": "Establish an ambient coroutine context from a Go context"
+  },
   "Main Function": {
     "prefix": "main",
     "body": [