lua output doc: Use more descriptive variable names in the examples

This also removes the "args" parameter of the hooking functions in the examples,
since this parameter is unused in all functions.
It would not be very helpful anyways since 3 of the 4 functions don't get passed
any parameters. The only exception is init() which gets a table containing:
  script_api_ver = 1

doc/userguide/output/lua-output.rst

@@ -57,12 +57,12 @@ Example:
       end
       http_ua = string.gsub(http_ua, "%g", ".")
 
-      ts = SCPacketTimeString()
+      timestring = SCPacketTimeString()
-      ipver, srcip, dstip, proto, sp, dp = SCFlowTuple()
+      ip_version, src_ip, dst_ip, protocol, src_port, dst_port = SCFlowTuple()
 
-      file:write (ts .. " " .. http_host .. " [**] " .. http_uri .. " [**] " ..
+      file:write (timestring .. " " .. http_host .. " [**] " .. http_uri .. " [**] " ..
-             http_ua .. " [**] " .. srcip .. ":" .. sp .. " -> " ..
+             http_ua .. " [**] " .. src_ip .. ":" .. src_port .. " -> " ..
-             dstip .. ":" .. dp .. "\n")
+             dst_ip .. ":" .. dst_port .. "\n")
       file:flush()
 
       http = http + 1
@@ -127,21 +127,22 @@ Add SCPacketTimeString to get the packets time string in the format:
 ::
 
   function log(args)
-      ts = SCPacketTimeString()
+      timestring = SCPacketTimeString()
+  end
 
 SCPacketTuple
 ~~~~~~~~~~~~~
 
 ::
 
-  ipver, srcip, dstip, proto, sp, dp = SCPacketTuple()
+  ip_version, src_ip, dst_ip, protocol, src_port, dst_port = SCPacketTuple()
 
 SCPacketPayload
 ~~~~~~~~~~~~~~~
 
 ::
 
-  p = SCPacketPayload()
+  payload = SCPacketPayload()
 
 flow
 ----
@@ -177,7 +178,7 @@ SCFlowTuple
 
 ::
 
-  ipver, srcip, dstip, proto, sp, dp = SCFlowTuple()
+  ip_version, src_ip, dst_ip, protocol, src_port, dst_port = SCFlowTuple()
 
 SCFlowAppLayerProto
 ~~~~~~~~~~~~~~~~~~~
@@ -399,8 +400,8 @@ DnsGetQueries
           rrtype = t["type"]
 
           print ("QUERY: " .. ts .. " " .. rrname .. " [**] " .. rrtype .. " [**] " ..
-                 "TODO" .. " [**] " .. srcip .. ":" .. sp .. " -> " ..
+                 "TODO" .. " [**] " .. src_ip .. ":" .. src_port .. " -> " ..
-                 dstip .. ":" .. dp)
+                 dst_ip .. ":" .. dst_port)
       end
   end
 
@@ -419,8 +420,8 @@ DnsGetAnswers
           ttl = t["ttl"]
 
           print ("ANSWER: " .. ts .. " " .. rrname .. " [**] " .. rrtype .. " [**] " ..
-                 ttl .. " [**] " .. srcip .. ":" .. sp .. " -> " ..
+                 ttl .. " [**] " .. src_ip .. ":" .. src_port .. " -> " ..
-                 dstip .. ":" .. dp)
+                 dst_ip .. ":" .. dst_port)
       end
   end
 
@@ -439,8 +440,8 @@ DnsGetAuthorities
           ttl = t["ttl"]
 
           print ("AUTHORITY: " .. ts .. " " .. rrname .. " [**] " .. rrtype .. " [**] " ..
-                 ttl .. " [**] " .. srcip .. ":" .. sp .. " -> " ..
+                 ttl .. " [**] " .. src_ip .. ":" .. src_port .. " -> " ..
-                 dstip .. ":" .. dp)
+                 dst_ip .. ":" .. dst_port)
       end
   end