[gcc r12-4354] doc: Fix typos in alloc_size documentation

[gcc r12-4354] doc: Fix typos in alloc_size documentation

[Jeff Law]

https://gcc.gnu.org/g:8226f6383a347371490897dba0383a7bc7082374

commit r12-4354-g8226f6383a347371490897dba0383a7bc7082374
Author: Daniel Le Duc Khoi Nguyen <greenrecyclebin@gmail.com>
Date:   Tue Oct 12 10:52:35 2021 -0400

    doc: Fix typos in alloc_size documentation
    
    gcc/
            * doc/extend.texi (Common Variable Attributes): Fix typos in
            alloc_size documentation.

Diff:
---
 gcc/doc/extend.texi | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
index 133b82eef38..10d466fae9a 100644
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -7359,10 +7359,10 @@ The @code{warn_if_not_aligned} attribute can also be used for types
 The @code{alloc_size} variable attribute may be applied to the declaration
 of a pointer to a function that returns a pointer and takes at least one
 argument of an integer type.  It indicates that the returned pointer points
-to an object whose size is given by the function argument at @var{position-1},
+to an object whose size is given by the function argument at @var{position},
 or by the product of the arguments at @var{position-1} and @var{position-2}.
 Meaningful sizes are positive values less than @code{PTRDIFF_MAX}.  Other
-sizes are disagnosed when detected.  GCC uses this information to improve
+sizes are diagnosed when detected.  GCC uses this information to improve
 the results of @code{__builtin_object_size}.
 
 For instance, the following declarations