fix(QrcodeStream.md): Fixed typo

In "did you requested the front camera although there is none?" the past tense is already inflected in the auxiliary verb "did", so the infinitive (base) form of the verb should be used here. 

Author: 777Vasya77

docs/api/QrcodeStream.md

@@ -131,15 +131,15 @@ This can happen [a couple of reasons](https://developer.mozilla.org/en-US/docs/W
 methods: {
   onError(error) {
     if (error.name === 'NotAllowedError') {
-      // user denied camera access permisson
+      // user denied camera access permission
     } else if (error.name === 'NotFoundError') {
       // no suitable camera device installed
     } else if (error.name === 'NotSupportedError') {
       // page is not served over HTTPS (or localhost)
     } else if (error.name === 'NotReadableError') {
       // maybe camera is already in use
     } else if (error.name === 'OverconstrainedError') {
-      // did you requested the front camera although there is none?
+      // did you request the front camera although there is none?
     } else if (error.name === 'StreamApiNotSupportedError') {
       // browser seems to be lacking features
     }