bug#14729: 24.3.50; Isearch oddity

[Juri Linkov]

>> `isearch-fail-pos' assumes that in a failed state of search
>> a shorter previous successful search string should be taken
>> as a basis for highlighting.  In this case, the last successful match
>> was "buf", so an appended suffix is highlighted as failed.
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> So, first we have:
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> Then we type "fer", and then get:
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> But...  I think I'd expect getting
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> instead?  Probably.

Or to turn the failing search into a successful one
since the search string matches the buffer.

OTOH, the current behavior also makes sense
since it highlights the last failing characters
typed by the user.  E.g. compare it with `C-s bufzzz'.