The important thing is that the encoding you (or, rather, your web server) declare in the
Content-Type HTTP header is the same one as you used when saving your source file.
It looks like you're saving your file as Windows-1252, which is not something I'd recommend on a public web site since it's Windows specific.
Either save the file as ISO 8859-1 or change the encoding declaration on the server to Windows-1252. Note, however, that this apostrophe is not available in the ISO encoding, so if you choose that way, you need to use an entity (’) or a reference (’).
Probably the best solution would be to use UTF-8. That means saving the file as UTF-8 and making the server send UTF-8 as the encoding declaration. UTF-8 can represent any character in the ISO 10646, which is the character repertoire used by HTML. (It's virtually the same thing as Unicode.)