Changed extension activation method

Author: nicopasla

package.json

@@ -34,7 +34,43 @@
     "student"
   ],
   "activationEvents": [
-    "onStartupFinished"
+    "onLanguage:'c'",
+    "onLanguage:'coffeescript'",
+    "onLanguage:'cpp'",
+    "onLanguage:'css'",
+    "onLanguage:'dockerfile'",
+    "onLanguage:'fsharp'",
+    "onLanguage:'go'",
+    "onLanguage:'groovy'",
+    "onLanguage:'haskell'",
+    "onLanguage:'ini'",
+    "onLanguage:'jade'",
+    "onLanguage:'java'",
+    "onLanguage:'javascript'",
+    "onLanguage:'javascriptreact'",
+    "onLanguage:'latex'",
+    "onLanguage:'less'",
+    "onLanguage:'lua'",
+    "onLanguage:'makefile'",
+    "onLanguage:'objective-c'",
+    "onLanguage:'ocaml'",
+    "onLanguage:'perl'",
+    "onLanguage:'perl6'",
+    "onLanguage:'php'",
+    "onLanguage:'plaintext'",
+    "onLanguage:'powershell'",
+    "onLanguage:'python'",
+    "onLanguage:'r'",
+    "onLanguage:'ruby'",
+    "onLanguage:'rust'",
+    "onLanguage:'scss'",
+    "onLanguage:'shellscript'",
+    "onLanguage:'sql'",
+    "onLanguage:'swift'",
+    "onLanguage:'typescript'",
+    "onLanguage:'typescriptreact'",
+    "onLanguage:'xsl'",
+    "onLanguage:'yaml'"
   ],
   "main": "./out/src/extension",
   "contributes": {