docs: Add missing symbols to various sections

docs/reference/libnice/libnice-sections.txt

@@ -14,6 +14,7 @@ NICE_AGENT_MAX_REMOTE_CANDIDATES
 nice_agent_new
 nice_agent_new_reliable
 nice_agent_new_full
+NiceAgentOption
 nice_agent_add_local_address
 nice_agent_set_port_range
 nice_agent_add_stream
@@ -62,6 +63,18 @@ nice_agent_get_type
 NICE_AGENT_CLASS
 NICE_IS_AGENT_CLASS
 NICE_AGENT_GET_CLASS
+NICE_TYPE_AGENT_OPTION
+NICE_TYPE_COMPATIBILITY
+NICE_TYPE_COMPONENT_STATE
+NICE_TYPE_COMPONENT_TYPE
+NICE_TYPE_NOMINATION_MODE
+NICE_TYPE_PROXY_TYPE
+nice_agent_option_get_type
+nice_compatibility_get_type
+nice_component_state_get_type
+nice_component_type_get_type
+nice_nomination_mode_get_type
+nice_proxy_type_get_type
 <SUBSECTION Private>
 NiceAgentClass
 </SECTION>
@@ -330,4 +343,9 @@ IS_PSEUDO_TCP_SOCKET
 IS_PSEUDO_TCP_SOCKET_CLASS
 <SUBSECTION Private>
 PseudoTcpSocketPrivate
+ECONNRESET
+EMSGSIZE
+ENOTCONN
+ETIMEDOUT
+EWOULDBLOCK
 </SECTION>