Drop wcwidth ASCII check

Updated widechar_width takes care of it.

Technically, this does ~3 comparisons more per-character (because it
checks variation selectors and such), but that shouldn't really matter.

src/fallback.cpp

@@ -269,10 +269,6 @@ int fish_get_emoji_width(wchar_t c) {
 #include "widecharwidth/widechar_width.h"
 
 int fish_wcwidth(wchar_t wc) {
-    // Normal ASCII characters.
-    // These are the most common case, so it's worth checking them first.
-    if (wc < 0x7f && wc >= 0x20) return 1;
-
     // The system version of wcwidth should accurately reflect the ability to represent characters
     // in the console session, but knows nothing about the capabilities of other terminal emulators
     // or ttys. Use it from the start only if we are logged in to the physical console.