maint: remove / fix many doubled words

Many source files have doubled words (eg "the the", "to to",
and so on). Most of these can simply be removed, but a couple
were actual mis-spellings (eg "to to" instead of "to do").
There was even one triple word score "to to to" :-)

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
diff --git a/include/exec/memory.h b/include/exec/memory.h
index b18b351..6a5fc9c 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -324,7 +324,7 @@
  * @owner: the object that tracks the region's reference count
  * @ops: a structure containing read and write callbacks to be used when
  *       I/O is performed on the region.
- * @opaque: passed to to the read and write callbacks of the @ops structure.
+ * @opaque: passed to the read and write callbacks of the @ops structure.
  * @name: used for debugging; not visible to the user or ABI
  * @size: size of the region.
  */