Documentation: Add UTF-8 Byte-Order-Mark to .rst files

Run bash code

 sed -i $'1 s/^/\xef\xbb\xbf/' Documentation/*.rst

to add the BOM.  This will allow strings like "Caché" to be represented
cleanly.

Change-Id: Iae303c5c8e38d098ce2e272b4a1b4455f1c10bb7