docs/manual/adding-packages-asciidoc.adoc: fix resources typo in example

As FOO_RESOURCES hints, the correct spelling is resources so use that.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

docs/manual/adding-packages-asciidoc.adoc

@@ -112,7 +112,7 @@ Here is a complete example that uses all variables and all hooks:
 05: ################################################################################
 06:
 07: FOO_SOURCES = $(sort $(wildcard $(FOO_DOCDIR)/*))
-08: FOO_RESOURCES = $(sort $(wildcard $(FOO_DOCDIR)/ressources))
+08: FOO_RESOURCES = $(sort $(wildcard $(FOO_DOCDIR)/resources))
 09:
 10: FOO_TOC_DEPTH = 2
 11: FOO_TOC_DEPTH_HTML = 1