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>