mu.subx: all parsing tests passing

apps/mu.subx

@@ -4642,7 +4642,7 @@ test-is-identifier-Z:
     5d/pop-to-ebp
     c3/return
 
-test-is-identifier-@:
+test-is-identifier-at:
     # character before 'A' is invalid
     # . prologue
     55/push-ebp

subx.vim

@@ -38,7 +38,7 @@ set cpo&vim
 setlocal formatoptions-=t  " allow long lines
 setlocal formatoptions+=c  " but comments should still wrap
 
-setlocal iskeyword+=-,?,<,>,$
+setlocal iskeyword+=-,?,<,>,$,@
 
 syntax match subxH1Comment /# - .*/ | highlight link subxH1Comment Comment
 syntax match subxComment /#\( \.\| - \|? \)\@!.*/ | highlight link subxComment Comment