Add buffer as a source for completion

.config/nvim/after/plugin/lsp.lua

@@ -1,4 +1,8 @@
-local lsp = require('lsp-zero').preset({})
+local lsp = require('lsp-zero').preset({
+	manage_nvim_cmp = {
+		set_sources = 'recommended',
+	}
+})
 local cmp = require('cmp');
 
 -- Set the lsp autocomplete to put text from selection into the buffer.

.config/nvim/lua/sheldonmlee/packer.lua

@@ -39,6 +39,7 @@ return require('packer').startup(function(use)
 			-- Autocompletion
 			{'hrsh7th/nvim-cmp'},     -- Required
 			{'hrsh7th/cmp-nvim-lsp'}, -- Required
+			{'hrsh7th/cmp-buffer'},
 			{'L3MON4D3/LuaSnip'},     -- Required
 		}
 	}