added return type void in SYNOPSIS

docs/curl_easy_cleanup.3

@@ -8,7 +8,7 @@ curl_easy_cleanup - End a libcurl session
 .SH SYNOPSIS
 .B #include <curl/curl.h>
 .sp
-.BI "curl_easy_cleanup(CURL *" handle ");"
+.BI "void curl_easy_cleanup(CURL *" handle ");"
 .ad
 .SH DESCRIPTION
 This function must be the last function to call for a curl session. It is the