opts: fixed some CURLOPT references so they get turned into links

docs/libcurl/opts/CURLOPT_ISSUERCERT.3

@@ -41,8 +41,8 @@ not considered as failure.
 
 A specific error code (CURLE_SSL_ISSUER_ERROR) is defined with the option,
 which is returned if the setup of the SSL/TLS session has failed due to a
-mismatch with the issuer of peer certificate (\fICURLOPT_SSL_VERIFYPEER\fP has
-to be set too for the check to fail). (Added in 7.19.0)
+mismatch with the issuer of peer certificate (\fICURLOPT_SSL_VERIFYPEER(3)\fP
+has to be set too for the check to fail). (Added in 7.19.0)
 .SH DEFAULT
 NULL
 .SH PROTOCOLS

docs/libcurl/opts/CURLOPT_OPENSOCKETFUNCTION.3

@@ -58,7 +58,7 @@ when doing active FTP. Future versions of libcurl may support more
 purposes.
 
 The \fIclientp\fP pointer contains whatever user-defined value set using the
-\fICURLOPT_OPENSOCKETDATA\fP function.
+\fICURLOPT_OPENSOCKETDATA(3)\fP function.
 
 The callback gets the resolved peer address as the \fIaddress\fP argument and
 is allowed to modify the address or refuse to connect completely. The callback

docs/libcurl/opts/CURLOPT_SOCKOPTFUNCTION.3

@@ -61,7 +61,7 @@ created socket descriptor to the callback in the \fIcurlfd\fP parameter so
 additional setsockopt() calls can be done at the user's discretion.
 
 The \fIclientp\fP pointer contains whatever user-defined value set using the
-\fICURLOPT_SOCKOPTDATA\fP function.
+\fICURLOPT_SOCKOPTDATA(3)\fP function.
 
 Return \fICURL_SOCKOPT_OK\fP from the callback on success. Return
 \fICURL_SOCKOPT_ERROR\fP from the callback function to signal an unrecoverable

docs/libcurl/opts/CURLOPT_WRITEDATA.3

@@ -38,7 +38,7 @@ The internal \fICURLOPT_WRITEFUNCTION(3)\fP will write the data to the FILE *
 given with this option, or to stdout if this option hasn't been set.
 
 If you're using libcurl as a win32 DLL, you \fBMUST\fP use the
-\fICURLOPT_WRITEFUNCTION\fP if you set this option or you will experience
+\fICURLOPT_WRITEFUNCTION(3)\fP if you set this option or you will experience
 crashes.
 .SH DEFAULT
 By default, this is a FILE * to stdout.