Documentation: remove duplicated words

Remove many duplicated words under Documentation/ and do other small
cleanups.

Examples:
        "and and" --> "and"
        "in in" --> "in"
        "the the" --> "the"
        "the the" --> "to the"
        ...

Signed-off-by: Paolo Ornati <ornati@fastwebnet.it>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
diff --git a/Documentation/filesystems/tmpfs.txt b/Documentation/filesystems/tmpfs.txt
index f9bcf9f..6dd0508 100644
--- a/Documentation/filesystems/tmpfs.txt
+++ b/Documentation/filesystems/tmpfs.txt
@@ -63,7 +63,7 @@
 nr_blocks: The same as size, but in blocks of PAGE_CACHE_SIZE.
 nr_inodes: The maximum number of inodes for this instance. The default
            is half of the number of your physical RAM pages, or (on a
-           a machine with highmem) the number of lowmem RAM pages,
+           machine with highmem) the number of lowmem RAM pages,
            whichever is the lower.
 
 These parameters accept a suffix k, m or g for kilo, mega and giga and