curl_url_set.3: fix typo in reference to CURLU_APPENDQUERY

docs/libcurl/curl_url_set.3

@@ -75,7 +75,7 @@ If used in with \fICURLU_APPENDQUERY\fP, the provided part will be appended on
 the end of the existing query - and if the previous part didn't end with an
 ampersand (&), an ampersand will be inserted before the new appended part.
 
-When \fCURLU_APPENDQUERY\fP is used together with \fICURLU_URLENCODE\fP,
+When \fICURLU_APPENDQUERY\fP is used together with \fICURLU_URLENCODE\fP,
 the '=' symbols will not be URL encoded.
 
 The question mark in the URL is not part of the actual query contents.