nvim: Pin base16 plug to last working version

HACK base16 plugin changed something in its internal application
of highlights so that not all highlights get correctly applied
when my nvim setup boots up. Have to investigate.

nvim/.config/nvim/lua/plugins/core.lua

@@ -41,6 +41,7 @@ return {
 		lazy = false,
 		priority = 1000,
 		dependencies = { "rktjmp/fwatch.nvim" },
+		commit = "96e3089", -- pin it to last commit before regression change
 	},
     -- try to avoid putting files in util buffers, e.g. filetree, aerial, undotree, ..
     {