refactor: Modify activationEvents (#29)

Author: beastmatser

package.json

@@ -131,7 +131,11 @@
     ]
   },
   "activationEvents": [
-    "onStartupFinished"
+    "onLanguage:viml",
+    "onLanguage:vim-help",
+    "onLanguage:vim-snippet",
+    "onLanguage:vim-markdown",
+    "workspaceContains:**/.*txt"
   ],
   "main": "./out/extension.js",
   "dependencies": {