(Info-search): In two similar places that skip

(Info-search): In two similar places that skip
undesired search matches move code to Info-search-success-function,
and call `isearch-success-function' instead.
(Info-search-success-function): New function copied from code
in Info-search.  Replace isearch-range-invisible with
text-property-not-all that checks for 'invisible and 'display
properties to skip partially invisible matches (whose display
properties were set by Info-fontify-node).
(Info-mode): Set buffer-local isearch-success-function
to Info-search-success-function.