"Player not playing" detection only works on English clients

[refaim]

Problem

In WIM_ChatFrame_OnEvent and WIM_ChatFrameSupressor_OnEvent, the system message parsing that detects "player is not currently playing" is hardcoded for the English locale:

local tstart,tfinish = string.find(arg1, "\'(%a+)\'");
...
tstart, tfinish = string.find(arg1, "playing");

This searches for the literal English word "playing" in the system message. On non-English clients (German, Russian, French, etc.), the system message has a different format and wording, so WIM never shows the "player is not currently playing" error in the chat window.

Expected behavior

The "not playing" message should be detected and displayed in WIM windows regardless of the client locale.

Possible fix

Use the localized ERR_CHAT_PLAYER_NOT_FOUND_S global string pattern (provided by the WoW client) to match the system message instead of hardcoding English text.