wip: add bufferline starting point

ref #56

lua/rose-pine/bufferline/init.lua

@@ -0,0 +1,23 @@
+local p = require('rose-pine.palette')
+
+-- TODO: Someone who uses bufferline.nvim is free to PR with this addition
+--       `:h bufferline-highlights`
+--
+--       The intended use would be (or any better solution):
+--
+--       ```
+--       local highlights = require('rose-pine.bufferline')
+--       require('bufferline').setup({
+--         highlights = highlights
+--       })
+--       ```
+return {
+	fill = {
+		guifg = p.text,
+		guibg = p.base,
+	},
+	background = {
+		guifg = p.text,
+		guibg = p.base,
+	},
+}