vim: more tweaks to lualine

1. Show the filename in italics if file is modified.
2. Put the plus sign on the right of the filename and make it stand out.
3. The symbols I was using were not rendering well on macOS and don't
   really have the time to debug this now. Just use simpler line.

config/nvim/after/plugin/lualine.lua

@@ -68,7 +68,6 @@ local parts = {
       local code = vim.api.nvim_get_mode().mode
       return MODE_MAP[code] or code
     end,
-    padding = 0,
   },
 
   visual_multi = function()
@@ -80,7 +79,6 @@ local parts = {
   branch = {
     'branch',
     icon = '',
-    padding = 0,
     cond = window_is_medium,
   },
 
@@ -95,10 +93,12 @@ local parts = {
       end
       return table.concat(flags, ' ')
     end,
-    padding = { left = 1, right = 0 },
+
+    color = { fg = '#eee8d5' },
   },
 
-  filename = function()
+  filename = {
+    function()
       local shorten_path = function(path)
         if window_is_wide() then
           return path
@@ -112,6 +112,15 @@ local parts = {
       return shorten_path(vim.fn.expand('%:~:.'))
     end,
 
+    color = function()
+      if vim.bo.modified then
+        return { gui = 'italic' }
+      end
+    end,
+
+    padding = { left = 1, right = 0},
+  },
+
   filetype = {
     filetype,
     cond = window_is_medium,
@@ -119,7 +128,6 @@ local parts = {
 
   fileformat = {
     'fileformat',
-    padding = { left = 0, right = 1 },
     cond = window_is_medium,
   },
 
@@ -132,27 +140,22 @@ local parts = {
     padding = { left = 0, right = 1 },
     cond = window_is_wide,
   },
-
-  location = {
-    'location',
-    padding = { left = 0, right = 1 },
-  },
 }
 
 local inactive_sections = {
   lualine_a = {},
-  lualine_b = { parts.visual_multi, parts.branch, parts.status },
-  lualine_c = { parts.filename },
+  lualine_b = { parts.visual_multi, parts.branch },
+  lualine_c = { parts.filename, parts.status },
   lualine_x = { 'diagnostics', parts.filetype  },
   lualine_y = { parts.fileformat, parts.progress },
-  lualine_z = { parts.location },
+  lualine_z = { 'location' },
 }
 
 require('lualine').setup {
   options = {
     icons_enabled = true,
     component_separators = { left = '', right = '' },
-    section_separators = { left = '', right = '' },
+    section_separators = { left = '', right = '' },
     theme = 'solarized',
   },