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/networking/sk98lin.txt b/Documentation/networking/sk98lin.txt
index 82ce554..4e1cc74 100644
--- a/Documentation/networking/sk98lin.txt
+++ b/Documentation/networking/sk98lin.txt
@@ -497,7 +497,7 @@
           www.syskonnect.com
           
           Some COMPAQ machines have problems dealing with PCI under Linux.
-          Linux. This problem is described in the 'PCI howto' document
+          This problem is described in the 'PCI howto' document
           (included in some distributions or available from the
           web, e.g. at 'www.linux.org').