ZP-1111 Fixed (C) copyright symbol.

Released under the Affero GNU General Public License (AGPL) version 3.

build/deb/debian.copyright

@@ -169,7 +169,7 @@ We have three specific requirements:
 
     2. Symbol: If reasonably possible, the first or most prominent mention of
        our registered Z-Push mark should be accompanied by a symbol indicating
-       that the mark is a registered trademark ("�").
+       that the mark is a registered trademark ("®").
 
     3. Distinguishable: In at least the first reference, the mark should be set
        apart from surrounding text, either by capitalizing it or by italicizing,