curl_easy_setopt: Fixed OAuth 2.0 Bearer option name

Bug: http://curl.haxx.se/bug/view.cgi?id=1313
Reported-by: Viktor Szakáts

docs/libcurl/curl_easy_setopt.3

@@ -1317,10 +1317,10 @@ mechanisms and to the IMAP, POP3 and SMTP protocols. (Added in 7.31.0)
 Note: Whilst IMAP supports this option there is no need to explicitly set it,
 as libcurl can determine the feature itself when the server supports the
 SASL-IR CAPABILITY.
-.IP CURLOPT_BEARER
-Pass a char * as parameter, which should point to the zero terminated OAUTH
-2.0 Bearer Access Token for use with IMAP. POP3 and SMTP servers that support
-the OAUTH 2.0 Authorization Framework. (Added in 7.33.0)
+.IP CURLOPT_XOAUTH2_BEARER
+Pass a char * as parameter, which should point to the zero terminated OAuth
+2.0 Bearer Access Token for use with IMAP, POP3 and SMTP servers that support
+the OAuth 2.0 Authorization Framework. (Added in 7.33.0)
 
 Note: The user name used to generate the Bearer Token should be supplied via
 the \fICURLOPT_USERNAME\fP option.