Use proper rdoc-ref to link to OpenSSL::SSL::SSLContext methods

Since `net-http` doesn't have its own documentation site and is always
included in the Ruby documentation, we should use the proper `rdoc-ref`
to link to `OpenSSL::SSL::SSLContext` methods, not linking to
`docs.ruby-lang.org`.

lib/net/http.rb

@@ -1546,11 +1546,11 @@ def use_ssl=(flag)
     attr_accessor :cert_store
 
     # Sets or returns the available SSL ciphers.
-    # See {OpenSSL::SSL::SSLContext#ciphers=}[https://docs.ruby-lang.org/en/master/OpenSSL/SSL/SSLContext.html#method-i-ciphers-3D].
+    # See {OpenSSL::SSL::SSLContext#ciphers=}[OpenSSL::SSL::SSL::Context#ciphers=].
     attr_accessor :ciphers
 
     # Sets or returns the extra X509 certificates to be added to the certificate chain.
-    # See {OpenSSL::SSL::SSLContext#add_certificate}[https://docs.ruby-lang.org/en/master/OpenSSL/SSL/SSLContext.html#method-i-add_certificate].
+    # See {OpenSSL::SSL::SSLContext#add_certificate}[OpenSSL::SSL::SSL::Context#add_certificate].
     attr_accessor :extra_chain_cert
 
     # Sets or returns the OpenSSL::PKey::RSA or OpenSSL::PKey::DSA object.
@@ -1560,15 +1560,15 @@ def use_ssl=(flag)
     attr_accessor :ssl_timeout
 
     # Sets or returns the SSL version.
-    # See {OpenSSL::SSL::SSLContext#ssl_version=}[https://docs.ruby-lang.org/en/master/OpenSSL/SSL/SSLContext.html#method-i-ssl_version-3D].
+    # See {OpenSSL::SSL::SSLContext#ssl_version=}[OpenSSL::SSL::SSL::Context#ssl_version=].
     attr_accessor :ssl_version
 
     # Sets or returns the minimum SSL version.
-    # See {OpenSSL::SSL::SSLContext#min_version=}[https://docs.ruby-lang.org/en/master/OpenSSL/SSL/SSLContext.html#method-i-min_version-3D].
+    # See {OpenSSL::SSL::SSLContext#min_version=}[OpenSSL::SSL::SSL::Context#min_version=].
     attr_accessor :min_version
 
     # Sets or returns the maximum SSL version.
-    # See {OpenSSL::SSL::SSLContext#max_version=}[https://docs.ruby-lang.org/en/master/OpenSSL/SSL/SSLContext.html#method-i-max_version-3D].
+    # See {OpenSSL::SSL::SSLContext#max_version=}[OpenSSL::SSL::SSL::Context#max_version=].
     attr_accessor :max_version
 
     # Sets or returns the callback for the server certification verification.
@@ -1584,7 +1584,7 @@ def use_ssl=(flag)
 
     # Sets or returns whether to verify that the server certificate is valid
     # for the hostname.
-    # See {OpenSSL::SSL::SSLContext#verify_hostname=}[https://docs.ruby-lang.org/en/master/OpenSSL/SSL/SSLContext.html#attribute-i-verify_mode].
+    # See {OpenSSL::SSL::SSLContext#verify_hostname=}[OpenSSL::SSL::SSL::Context#verify_hostname=].
     attr_accessor :verify_hostname
 
     # Returns the X509 certificate chain (an array of strings)