package/archlinux: report missed lines in coverage output.

And turn off function coverage, it isn't useful.

package/archlinux/PKGBUILD-coverage

@@ -60,7 +60,7 @@ check() {
     # TODO figure out a way to avoid adding --ignore-errors mismatch etc
     lcov --ignore-errors mismatch,inconsistent --directory . --capture --output-file coverage.info
     lcov --extract coverage.info "*/src/python/*" "*/src/Corrade/*" "*/src/Magnum/*" --output-file coverage.info
-    genhtml --output-directory ./coverage coverage.info
+    genhtml --no-function-coverage --missed --output-directory ./coverage coverage.info
 }
 
 package() {