[PATCH][documentation] Fix typo in access function attribute example

[Forrest Timour via Gcc-patches]

Hi,

This patch fixes an off-by-one typo in the documentation example of the
access function attribute.

This is my first contribution and I don't have write access, so I will need
somebody to submit for me on approval.

Thanks,
Forrest

-------------------------------------------------------
Fix typo in documentation example of access function
attribute where the ref-indices should be one-indexed
instead of zero-indexed

2020-06-16  Forrest Timour  <forrest.tim...@gmail.com>

gcc/ChangeLog:

        * doc/extend.texi:
---
 gcc/doc/extend.texi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
index e656e66a80c..10dc32e6d2d 100644
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -2527,7 +2527,7 @@ the @code{memcpy} function.
 
 @smallexample
 __attribute__ ((access (read_only, 1))) int puts (const char*);
-__attribute__ ((access (read_only, 1, 2))) void* memcpy (void*, const void*, size_t);
+__attribute__ ((access (read_only, 2, 3))) void* memcpy (void*, const void*, size_t);
 @end smallexample
 
 The @code{read_write} access mode applies to arguments of pointer types