add extendend_integration for vim-illuminate (#259)

Co-authored-by: Indelog <contact@indelog.fr>

lua/base46/integrations/illuminate.lua

@@ -0,0 +1,7 @@
+local colors = require("base46").get_theme_tb "base_30"
+
+return {
+  IlluminatedWordText = { bold = true, reverse = true },
+  IlluminatedWordRead = { bold = true, reverse = true },
+  IlluminatedWordWrite = { bold = true, reverse = true },
+}