A small typo in customize group doc

[Teemu Likonen]

There is a small typo in the document string of customize group
"sh-indentation":

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diff --git i/lisp/progmodes/sh-script.el w/lisp/progmodes/sh-script.el
index ca0971b..610fa14 100644
--- i/lisp/progmodes/sh-script.el
+++ w/lisp/progmodes/sh-script.el
@@ -1185,9 +1185,9 @@ subshells can nest."
 (defgroup sh-indentation nil
   "Variables controlling indentation in shell scripts.
 
 Note: customizing these variables will not affect existing buffers if
-`sh-make-vars-local' is no-nil.  See the documentation for
+`sh-make-vars-local' is non-nil.  See the documentation for
 variable `sh-make-vars-local', command `sh-make-vars-local'
 and command `sh-reset-indent-vars-to-global-values'."
   :group 'sh-script)
 
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