[PATCH] doc: fix another bad <at> xref

Obviously, I didn't fully test commit f35498d.

* doc/autoconf.texi (Limitations of Builtins): Add a comma.

Signed-off-by: Eric Blake <eblake <at> redhat.com>
---
 doc/autoconf.texi |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index 34ca213..393e38f 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
 <at>  <at>  -17874,7 +17874,7  <at>  <at>  Limitations of Builtins
  <at> samp{-}. With Solaris  <at> command{ksh}, it is possible to use  <at> code{print
 -r --} for this role instead.

- <at> xref{echo, , Limitations of Shell Builtins} for a discussion of
+ <at> xref{echo, , Limitations of Shell Builtins}, for a discussion of
 portable alternatives to both  <at> command{printf} and  <at> command{echo}.

--

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1.7.7.6