Add missing codepoints to isPowerline predicate

e0d6 and e0d7 were left out.

Also collapsed everything to a single range; unlikely that the unused
gaps (e0c9, e0cb, e0d3, e0d5) would be used for something else in any
font that ships Powerline glyphs.

src/renderer/cell.zig

@@ -352,7 +352,7 @@ fn isLegacyComputing(char: u21) bool {
 // Returns true if the codepoint is a part of the Powerline range.
 fn isPowerline(char: u21) bool {
     return switch (char) {
-        0xE0B0...0xE0C8, 0xE0CA, 0xE0CC...0xE0D2, 0xE0D4 => true,
+        0xE0B0...0xE0D7 => true,
         else => false,
     };
 }