Add support for untracked local snippets

lua/plugins/snippets.lua

@@ -6,8 +6,14 @@ return {
     local luasnip = require('luasnip')
     luasnip.setup({})
 
-    -- Load snippets
-    local opts = { paths = vim.fn.stdpath('config') .. '/snippets' }
+    -- Load snippets. The 'snippets/local' directory is gitignored and holds
+    -- personal snippets that are not tracked; LuaSnip merges it with the
+    -- tracked snippets above.
+    local config_dir = vim.fn.stdpath('config')
+    local opts = { paths = {
+      config_dir .. '/snippets',
+      config_dir .. '/snippets/local',
+    } }
     require('luasnip.loaders.from_snipmate').lazy_load(opts)
     require('luasnip.loaders.from_lua').lazy_load(opts)