transposed two letters in a comment

xpcom/reflect/xptcall/public/genstubs.pl

@@ -8,7 +8,7 @@
 # if "$entry_count" is ever changed and the .inc files regenerated then
 # the following issues need to be addressed:
 #
-# 1) Alpah NT has a .def file that lists exports by symbol. It will need
+# 1) Alpha NT has a .def file that lists exports by symbol. It will need
 #    updating.
 # 2) The current Linux ARM code has a limitation of only having 256-3 stubs
 #