Remove highlight configs

`bat` has completely taken over this use-case

.highlight/themes/base16.theme

@@ -1,25 +0,0 @@
---%%base16_template: highlight##default %%
-Description = "Base16 "
-
-Default = { Colour = "#f0f0f0" }
-Canvas = { Colour="#000000" }
-Number = { Colour="#f7941d" }
-Escape = { Colour="#c0c0c0" , Italic=true}
-String = { Colour="#8dc73f" }
-BlockComment = { Colour="#606060" }
-StringPreProc = String
-LineComment   = BlockComment
-Operator      = { Colour="#f0f0f0" }
-LineNum      = { Color="#606060" }
-PreProcessor      = { Colour="#a16946" }
-Interpolation  = Escape
-
-Keywords = {
-  { Colour="#ed008c", Bold=true},
-  { Colour="#f7c61d"},
-  { Colour="#3f7fff"},
-  { Colour="#f7c61d"},
-  { Colour="#f7c61d" }
-}
-
--- %%base16_template_end%%