irc: fix gettext shadowing by avoiding '_' loop variables (Switch channel, receive loop)

Signed-off-by: Slendi <slendi@socopon.com>

main.lua

@@ -299,7 +299,7 @@ function IrcChatView:receiveLoop()
     if self._closing then return end
     if not self._sock then return end
     -- Non-blocking receive lines; iterate until no more data
-    for _ = 1, 50 do -- cap per tick
+    for i = 1, 50 do -- cap per tick
         local line, err, partial = self._sock:receive("*l")
         if line then
             self:handleLine(line)
@@ -493,7 +493,7 @@ function IrcChatView:showChannelSwitcher()
     local Menu = require("ui/widget/menu")
     local items = {}
     local targets = self._ordered_targets or {}
-    for _, tgt in ipairs(targets) do
+    for i, tgt in ipairs(targets) do
         local label = (tgt == "*" and _("Server console")) or tgt
         table.insert(items, {
             text_func = function()
@@ -894,7 +894,7 @@ function IRC:connectToServer(server)
     if server.channels and #server.channels > 1 then
         -- Prompt to pick a channel
         local buttons = {}
-        for _, ch in ipairs(server.channels) do
+        for i, ch in ipairs(server.channels) do
             table.insert(buttons, { { text = ch, callback = function() UIManager:close(self._chan_dlg); open_chat(ch) end } })
         end
         self._chan_dlg = require("ui/widget/buttondialog"):new{