Set up normal obsidian naming conventions

lua/core/plugin_config/obsidian.lua

@@ -20,4 +20,18 @@ require("obsidian").setup({
     -- A map for custom variables, the key should be the variable and the value a function
     substitutions = {},
   },
+  note_id_func = function(title)
+    local suffix = ""
+    if title ~= nil then
+      -- If title is given, transform it into valid file name.
+      suffix = title:gsub(" ", "-"):gsub("[^A-Za-z0-9-]", ""):lower()
+    else
+      -- If title is nil, just add 4 random uppercase letters to the suffix.
+      for _ = 1, 4 do
+        suffix = suffix .. string.char(math.random(65, 90))
+      end
+    end
+    return suffix
+  end,
+
 })