JFYI: I've just checked: InternetArchiveBot still behaves in the that way. I.e. it can break stuff a-la {{Cite web|archiveurl=https://www.webcitation.org/…}}.

• стели іs: (1) singular genitive of сте́ла ("stele"), (2) imperative mood of стели́ти ("to lay down");
  • стелю is: (1) first person singular of стели́ти ("to lay down"), (2) singular dative of сте́ля ("ceiling");
  • слати is: (1) "to send", (2) alternative (archaic?) form for стели́ти ("to lay down");
  • шлем is: (1) alternative of шлемо́, which is first person plural of сла́ти ("to send"); (2) colloquial for шоло́м ("helmet").

Well Russian, Ukrainian and Belorussian are quite close. (Polish is close too, some claim that it's even closer to Ukrainian than Russian — but as Polish uses different alphabet, it seems to be out of scope.) (BTW, what is about Belorussian? Does it use different lexical analyzer? Theoretically, it may fit Ukrainian even better than Russian.)

though I do worry about languages that might use the apostrophe as a proper letter

Sorry for stupid question, but what is difference between apostrophe-as-proper-letter and apostrophe-as-part-of-word-but-still-not-considered-a-letter? I.e. I understand difference between apostrophe-as-part-of-word and apostrophe-as-punctuation-mark: in first case "abc'def" gives one lexeme, and in second it gives two lexemes ("abc" and "def"). But I don't understand what is practical difference for search between something considered a letter and something considered a part of a word (but still not letter).

@TJones, IMHO treating all three apostrophes (U+0027, U+2019, U+02BC) as one sign in search shouldn't harm Russian or any other languages using Russian-language analyzer.