oauthutil: clarify token replacement prompt wording

The previous wording "Already have a token - refresh?" was misleading
because answering yes triggers a full re-authorization flow, not an
OAuth2 refresh token grant. Updated to "Token already configured -
replace it?" to accurately describe what happens.

Also updated the SugarSync backend which has its own copy of the prompt,
and the docs for box, drive, and onedrive that reference it.

docs/content/box.md

@@ -183,7 +183,7 @@ y) Yes
 n) No
 y/n> n
 Remote config
-Already have a token - refresh?
+Token already configured - replace it?
 y) Yes
 n) No
 y/n> y

docs/content/drive.md

@@ -2009,7 +2009,7 @@ Scroll down and click "+ Add users". Add yourself as a test user and press save.
 10. Provide the noted client ID and client secret to rclone.
 
 11. Run the web-based authorization flow from within `rclone config`, by answering
-    "Y" when it asks "Already have a token - refresh?".
+    "Y" when it asks "Token already configured - replace it?".
 
 Be aware that, due to the "enhanced security" recently introduced by
 Google, you are theoretically expected to "submit your app for verification"

docs/content/onedrive.md

@@ -1243,7 +1243,7 @@ If you see the error above after enabling multi-factor authentication for your
 account, you can fix it by refreshing your OAuth refresh token. To do that, run
 `rclone config`, and choose to edit your OneDrive backend. Then, you don't need
 to actually make any changes until you reach this question:
-`Already have a token - refresh?`. For this question, answer `y` and go through
+`Token already configured - replace it?`. For this question, answer `y` and go through
 the process to refresh your token, just like the first time the backend is
 configured. After this, rclone should work again for this backend.