Template changes

Since my markdown templates use `Title` and the keyword for the filename
and my ReadingList template also used `Title` as a keyword, my
automations were getting confused.

I changed `Title` in the markdown template to `filename` to solve.

Also, I reverted my `poor man's surround` keybindings for an actual
plugin: `tpope/vim-surround`

.vim/templates/md

@@ -1,9 +1,8 @@
 :insert
-# title
+# filename
 
 - Created :
 - Updated : 
 
 ---
 
-