Documentation/filesystems/proc.txt: indentation fix

Signed-off-by: Adrian Bunk <bunk@stusta.de>
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index a4dcf42..944cf10 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -418,7 +418,7 @@
        Dirty: Memory which is waiting to get written back to the disk
    Writeback: Memory which is actively being written back to the disk
       Mapped: files which have been mmaped, such as libraries
-              Slab: in-kernel data structures cache
+        Slab: in-kernel data structures cache
  CommitLimit: Based on the overcommit ratio ('vm.overcommit_ratio'),
               this is the total amount of  memory currently available to
               be allocated on the system. This limit is only adhered to