Update comment in Lua script

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: airween

test/test-cases/data/match-getvars.lua

@@ -2,9 +2,9 @@ function dump(o)
    if type(o) == 'table' then
       local s = '{ '
       for k,v in pairs(o) do
-         -- we create a local var because in Lua55
-         -- variables k and v get an implicit 'const' modifier
-         -- this works in previous Lua versions too
+         -- In Lua 5.5, generic-for loop variables (k and v) are read-only,
+         -- so we copy k into a local before formatting. This works in earlier
+         -- Lua versions too.
          local key_str = k
          if type(key_str) ~= 'number' then
             key_str = '"'..key_str..'"'