Fix menu localization not updated for "Open Tab..." item (#12993)

THe menu item "Open Tab..." was changed to "Open &Tab..." in #12895 but
localization files were not updated. Update it here.

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/lang/menu_is_is.latin1.vim b/runtime/lang/menu_is_is.latin1.vim
index bcb7096..102dede 100644
--- a/runtime/lang/menu_is_is.latin1.vim
+++ b/runtime/lang/menu_is_is.latin1.vim
@@ -23,7 +23,7 @@
 menutrans &File				                        Skrá
 menutrans &Open\.\.\.<Tab>:e		                Opna\.\.\.<Tab>:e
 menutrans Sp&lit-Open\.\.\.<Tab>:sp	                Splitt\ opna\.\.\.<Tab>:sp
-menutrans Open\ Tab\.\.\.<Tab>:tabnew	            Opna\ flipa\.\.\.<Tab>:tabnew
+menutrans Open\ &Tab\.\.\.<Tab>:tabnew	            Opna\ flipa\.\.\.<Tab>:tabnew
 menutrans &New<Tab>:enew		                    Ný\ Skrá<Tab>:enew
 menutrans &Close<Tab>:close		                    Loka<Tab>:close
 menutrans &Save<Tab>:w			                    Vista<Tab>:w