It does (U+0131 = Latin Small Letter Dotless I, U+0069 = Latin Small Letter I).
The problem is that uppercasing the dotted i outputs a different character depending on your current locale. Using case-insensitive equality checks also break this way (I==i, except in a Turkish locale, so `QUIT ilike quit` is false).
Yes - the problem is that "i" and "I" are standard ASCII characters, while the dotted I and the dotless i are not. Creating special "Turkish I" and "Turkish i" characters would have been an alternative, but would have had its own issues (e.g. documents where only some "i"s are Turkish and the rest "regular" because different people edited it with different software/settings).
Irish script traditionally used a dot-less "i", something that persists in current road signage (anecdotally to save confusion with "í", or with adjacent old-style dotted consonants, I can't find a definitive source to cite). It's only an orthographic/type thing, it's semantically an "i", though the Unicode dot-less "i" is sometimes used online to represent it.
Is it? That's weird, I can't find the code for Latin Small Letter Dotted I. There is a Cyrillic dotted I, but that one doesn't have the dot in capitalised form.
What sebstefan is asking for is a Unicode character which is the non-capitalised form of Latin Capital Letter I With Dot Above (U+0130) which always gets capitalised to U+0130 and which U+0130 gets downcased to.
The problem is that uppercasing the dotted i outputs a different character depending on your current locale. Using case-insensitive equality checks also break this way (I==i, except in a Turkish locale, so `QUIT ilike quit` is false).