Fix a special case in concat one letter flags.

When both "-x" and "-x-" were specified, then the "-x-" accidentally
disabled one letter concat support for "-x".

completions/dirx.lua

@@ -320,7 +320,6 @@ end
 -- the hide_unless stuff in general.
 local minus_flags = { concat_one_letter_flags=true, onarg=onarg_dirxcmd }
 local slash_flags = { concat_one_letter_flags=true }
-local one_letter_flags = {}
 
 local function copy_vars(entry, tbl)
     tbl.hide = entry.hide
@@ -352,11 +351,6 @@ for _, entry in ipairs(list_of_flags) do
     else
         error("unrecognized flag entry format.")
     end
-
-    if not long then
-        table.insert(one_letter_flags, minus)
-        table.insert(one_letter_flags, slash)
-    end
 end
 
 clink.argmatcher("dirx")

modules/arghelper.lua

@@ -477,7 +477,8 @@ if not tmp._addexflags or not tmp._addexarg then
     end
 
     local function maybe_one_letter_flag(concat_flags, flag, arginfo, linked)
-        if is_one_letter_flag(flag) then
+        local letter,plusminus = is_one_letter_flag(flag)
+        if letter then
             table.insert(concat_flags, flag)
             local tbl = concat_flags[flag]
             if not tbl then
@@ -491,7 +492,7 @@ if not tmp._addexflags or not tmp._addexarg then
                 tbl.one_letter_linked = true
             end
         end
-        if #flag > 2 then
+        if #flag > 2 and not plusminus then
             local flag2 = flag:sub(1, 2)
             if is_one_letter_flag(flag2) and concat_flags[flag2] then
                 concat_flags[flag2].one_letter_arginfo = true