feat(config): support for 5 code point glyphs in export

relates to https://github.com/ryanoasis/nerd-fonts/issues/365#issuecomment-1398110379

src/engine/config.go

@@ -235,13 +235,54 @@ func (cfg *Config) backup() {
 }
 
 func escapeGlyphs(s string) string {
+	shouldExclude := func(r rune) bool {
+		if r < 0x1000 { // Basic Multilingual Plane
+			return true
+		}
+		if r > 0x1F600 && r < 0x1F64F { // Emoticons
+			return true
+		}
+		if r > 0x1F300 && r < 0x1F5FF { // Misc Symbols and Pictographs
+			return true
+		}
+		if r > 0x1F680 && r < 0x1F6FF { // Transport and Map
+			return true
+		}
+		if r > 0x2600 && r < 0x26FF { // Misc symbols
+			return true
+		}
+		if r > 0x2700 && r < 0x27BF { // Dingbats
+			return true
+		}
+		if r > 0xFE00 && r < 0xFE0F { // Variation Selectors
+			return true
+		}
+		if r > 0x1F900 && r < 0x1F9FF { // Supplemental Symbols and Pictographs
+			return true
+		}
+		if r > 0x1F1E6 && r < 0x1F1FF { // Flags
+			return true
+		}
+		return false
+	}
+
 	var builder strings.Builder
 	for _, r := range s {
-		// exclude regular characters and emoji
-		if r < 0x1000 || r > 0x10000 {
+		// exclude regular characters and emojis
+		if shouldExclude(r) {
 			builder.WriteRune(r)
 			continue
 		}
+
+		if r > 0x10000 {
+			// calculate surrogate pairs
+			one := 0xd800 + (((r - 0x10000) >> 10) & 0x3ff)
+			two := 0xdc00 + ((r - 0x10000) & 0x3ff)
+			quoted := fmt.Sprintf("\\u%04x\\u%04x", one, two)
+			builder.WriteString(quoted)
+			continue
+		}
+
 		quoted := fmt.Sprintf("\\u%04x", r)
 		builder.WriteString(quoted)
 	}

src/engine/config_test.go

@@ -49,6 +49,7 @@ func TestEscapeGlyphs(t *testing.T) {
 		Input    string
 		Expected string
 	}{
+		{Input: "󰉋", Expected: "\\udb80\\ude4b"},
 		{Input: "a", Expected: "a"},
 		{Input: "\ue0b4", Expected: "\\ue0b4"},
 		{Input: "\ufd03", Expected: "\\ufd03"},