refactor(vim): simplify the tab behaviour in completion

The biggest change here is that I am no longer cycling though completion
items as the first thing. Tab will now mainly control the snippet jumps
in completion not items. Completion items can be used exclusively with
<C-n> and <C-p> and <CR> to complete the selected item. If the
completion menu is open and <CR> is pressed, this will select and
complete the first item.

I will soon be able to remove the <C-h> and <C-l> mappings when my
muscle memory adapts as this will now be controlled with tab.

site-modules/core/files/vim/init.vim

@@ -74,6 +74,3 @@ nnoremap <leader><tab> <c-^>
 " ignored from command-t file searches.
 let g:CommandTWildIgnore="*/node_modules/*,*/vendor/*,*/runtime/*,*/public_html/*,*/pack/*"
 
-" Required for complietion with nvim-cmp
-set completeopt=menu,menuone,noselect
-

site-modules/core/files/vim/plugin/completion.lua

@@ -28,11 +28,6 @@ Text = "",
     Operator = "",
 }
 
-local has_words_before = function()
-  local line, col = unpack(vim.api.nvim_win_get_cursor(0))
-  return col ~= 0 and vim.api.nvim_buf_get_lines(0, line - 1, line, true)[1]:sub(col, col):match("%s") == nil
-end
-
 cmp.setup({
     mapping = cmp.mapping.preset.insert({
         ['<C-j>'] = cmp.get_config().mapping['<Down>'],
@@ -41,29 +36,17 @@ cmp.setup({
         ['<C-h>'] = function() luasnip.jump(-1) end,
 
         ['<C-e>'] = cmp.mapping.abort(),
-        ['<CR>'] = cmp.mapping(function(_fallback)
+        ['<CR>'] = cmp.mapping.confirm({ select = true }),
-            if cmp.visible() then
-                cmp.confirm({ select = true })
-            else
-                vim.api.nvim_feedkeys('\n', 'nt', false)
-            end
-        end, { 'i', 's' }),
         ["<Tab>"] = cmp.mapping(function(fallback)
-            if cmp.visible() then
+            if luasnip.expand_or_jumpable() then
-                cmp.select_next_item()
-            elseif luasnip.expand_or_jumpable() then
                 luasnip.expand_or_jump()
-            elseif has_words_before() then
-                cmp.complete()
             else
                 fallback()
             end
         end, { "i", "s" }),
 
         ["<S-Tab>"] = cmp.mapping(function(fallback)
-            if cmp.visible() then
+            if luasnip.jumpable(-1) then
-                cmp.select_prev_item()
-            elseif luasnip.jumpable(-1) then
                 luasnip.jump(-1)
             else
                 fallback()