Documentation/gitcredentials.txt: mention password alternatives

Git asks for a "password", but the user might use a
personal access token or OAuth access token instead.

Example:

    Password for 'https://[email protected]':

Signed-off-by: M Hickford <[email protected]>
Signed-off-by: Taylor Blau <[email protected]>

Author: hickford

Documentation/gitcredentials.txt

@@ -17,9 +17,10 @@ DESCRIPTION
 
 Git will sometimes need credentials from the user in order to perform
 operations; for example, it may need to ask for a username and password
-in order to access a remote repository over HTTP. This manual describes
-the mechanisms Git uses to request these credentials, as well as some
-features to avoid inputting these credentials repeatedly.
+in order to access a remote repository over HTTP. Some remotes accept
+a personal access token or OAuth access token as a password. This
+manual describes the mechanisms Git uses to request these credentials,
+as well as some features to avoid inputting these credentials repeatedly.
 
 REQUESTING CREDENTIALS
 ----------------------