Typo

(cherry picked from commit 62c9804680ae28a804c814feeafb857ddbfaaba8)

Source commit: 5e1a81b222cb73ceb31dc9f7574b2ba273ee8621

source/windows/Setup.cpp

@@ -136,7 +136,7 @@ void path_reg_propagate()
   {
     err_out_sys(_T("Cannot propagate the new enviroment to ")
                 _T("other processes. The new value will be ")
-                _T("avaible after a reboot."), GetLastError());
+                _T("available after a reboot."), GetLastError());
     SimpleErrorDialog(LastPathError);
     LastPathError = L"";
   }