trivial: manual: multimedia is no longer a subdirectory

Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

docs/manual/adding-packages-directory.txt

@@ -8,7 +8,7 @@ First of all, create a directory under the +package+ directory for
 your software, for example +libfoo+.
 
 Some packages have been grouped by topic in a sub-directory:
-+multimedia+, +x11r7+, +efl+ and +matchbox+. If your package fits in
++x11r7+, +efl+ and +matchbox+. If your package fits in
 one of these categories, then create your package directory in these.
 New subdirectories are discouraged, however.