Fix some typos in Documentation/: 'A'

This patch fixes typos in various Documentation txts.
This patch addresses some words starting with the letter 'A'.

Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
diff --git a/Documentation/keys.txt b/Documentation/keys.txt
index e373f02..5745090 100644
--- a/Documentation/keys.txt
+++ b/Documentation/keys.txt
@@ -708,7 +708,7 @@
 
      If the specified key is 0, then any assumed authority will be divested.
 
-     The assumed authorititive key is inherited across fork and exec.
+     The assumed authoritative key is inherited across fork and exec.
 
 
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