feat: set up luasnip;

feat: markdown file marker snippet

nvim/lua/snippets/markdown.lua

@@ -0,0 +1,34 @@
+local ls = require("luasnip")
+local s = ls.snippet
+local t = ls.text_node
+local i = ls.insert_node
+local f = ls.function_node
+local extras = require("luasnip.extras")
+local rep = extras.rep
+
+local timestamp = function()
+  return tostring(os.time())
+end
+
+local get_date = function()
+  return os.date("%H:%M:%S %d.%m.%Y")
+end
+
+local get_name = function()
+  return "Nikolai Papin"
+end
+
+return {
+  s("frontmatter", {
+    t("---"),
+    t({ "", "title: \"" }), i(1), t("\""),
+    t({ "", "date: " }), f(get_date, {}),
+    t({ "", "author: \"" }), f(get_name, {}), t("\""),
+    t({ "", "id: " }), f(timestamp, {}),
+    t({ "", "---", "", "# " }),
+    rep(1),  -- Reuses the first insert node
+    t({ "", ""}),
+    t({ "", ""}),
+    i(3)     -- Final cursor position
+  })
+}