fix: update color format in fastfetch scripts for compatibility

config/fastfetch/.config/fastfetch/apply-color

@@ -8,7 +8,13 @@
 
 file="$HOME/.config/fish/conf.d/60-fetch.fish"
 
-sed -i -E "s/(set -g fetch_color\s+\"#)([0-9a-fA-F]{6})(\")/\1${colorHex}\3/" "$file" || {
+# "#rrggbb" format is only available in and after fastfetch v2.42.0,
+# so we use the equivalent "ANSI Escape Sequences" format for compatibility.
+# Luckily we have a helper function that can convert something like "rrggbb"
+# into "\033[38;2;rrr;ggg;bbbm", which was meant to be used in log messages.
+colorAnsi=$(color_ansi "$colorHex" | sed -E "s/(.\[)([0-9;\]+)(m)/\2/")
+
+sed -i -E "s/(set -g fetch_color\s+\")([0-9;]+)(\")/\1${colorAnsi}\3/" "$file" || {
 	log_error "Failed to edit ${file}"
 	exit 1
 }