Implement semantic theme color system

default/themed/helix.toml.tpl

@@ -121,12 +121,12 @@ foreground = "{{ foreground }}"
 cursor = "{{ cursor }}"
 selection_background = "{{ selection_background }}"
 selection_foreground = "{{ selection_foreground }}"
-color0 = "{{ color0 }}"
-color1 = "{{ color1 }}"
-color2 = "{{ color2 }}"
-color3 = "{{ color3 }}"
-color4 = "{{ color4 }}"
-color5 = "{{ color5 }}"
-color6 = "{{ color6 }}"
-color7 = "{{ color7 }}"
-color8 = "{{ color8 }}"
+color0 = "{{ background }}"
+color1 = "{{ red }}"
+color2 = "{{ green }}"
+color3 = "{{ yellow }}"
+color4 = "{{ blue }}"
+color5 = "{{ purple }}"
+color6 = "{{ cyan }}"
+color7 = "{{ foreground }}"
+color8 = "{{ muted }}"