chore(fmt): Finally let's use stylua

Hoping it's as good as go-fmt

lua/outline/ui.lua

@@ -1,26 +1,19 @@
 local M = {}
 
-M.hovered_hl_ns = vim.api.nvim_create_namespace 'hovered_item'
+M.hovered_hl_ns = vim.api.nvim_create_namespace('hovered_item')
 
 function M.clear_hover_highlight(bufnr)
   vim.api.nvim_buf_clear_namespace(bufnr, M.hovered_hl_ns, 0, -1)
 end
 
 function M.add_hover_highlight(bufnr, line, col_start)
-  vim.api.nvim_buf_add_highlight(
-    bufnr,
-    M.hovered_hl_ns,
-    'OutlineCurrent',
-    line,
-    col_start,
-    -1
-  )
+  vim.api.nvim_buf_add_highlight(bufnr, M.hovered_hl_ns, 'OutlineCurrent', line, col_start, -1)
 end
 
 function M.setup_highlights()
   -- Setup the OutlineCurrent highlight group if it hasn't been done already by
   -- a theme or manually set
-  if vim.fn.hlexists 'OutlineCurrent' == 0 then
+  if vim.fn.hlexists('OutlineCurrent') == 0 then
     -- TODO: Use nvim_get_hl
     local cline_hl = vim.api.nvim_get_hl_by_name('CursorLine', true)
     local string_hl = vim.api.nvim_get_hl_by_name('String', true)
@@ -36,16 +29,10 @@ function M.setup_highlights()
   -- notably making them italic, which messes up the outline connector. Fix
   -- this by copying the foreground color from the comment hl into a new
   -- highlight.
-  local comment_fg_gui = vim.fn.synIDattr(
-    vim.fn.synIDtrans(vim.fn.hlID 'Comment'),
-    'fg',
-    'gui'
-  )
+  local comment_fg_gui = vim.fn.synIDattr(vim.fn.synIDtrans(vim.fn.hlID('Comment')), 'fg', 'gui')
 
-  if vim.fn.hlexists 'OutlineGuides' == 0 then
-    vim.cmd(
-      string.format('hi OutlineGuides guifg=%s', comment_fg_gui)
-    )
+  if vim.fn.hlexists('OutlineGuides') == 0 then
+    vim.cmd(string.format('hi OutlineGuides guifg=%s', comment_fg_gui))
   end
 end