vimrc: update color settings

vim/after/ftplugin/go.vim

@@ -56,7 +56,8 @@ let g:go_auto_type_info = 0
 let g:go_code_completion_enabled = 1
 let g:go_echo_command_info = 0
 let g:go_echo_go_info = 0
-let g:go_highlight_functions = 1
+let g:go_highlight_diagnostic_errors = 0
+let g:go_highlight_diagnostic_warnings = 0
 " g:go_statusline_duration doesn't seem to work accurately, but does help:
 let g:go_statusline_duration = 1000
 let g:go_gopls_analyses = {

vimrc

@@ -79,10 +79,29 @@ endif
 
 " Colour scheme:
 packadd! gruvbox
-let g:gruvbox_contrast_dark='soft'
-let g:gruvbox_contrast_light='soft'
+let g:gruvbox_contrast_dark='medium'
+let g:gruvbox_contrast_light='medium'
+let g:gruvbox_improved_strings=1
+let g:gruvbox_improved_warnings=1
+let g:gruvbox_vert_split='bg2'
 colorscheme gruvbox
 
+function! SwitchBackground()
+  if &background == 'dark'
+    set background=light
+    let g:lightline.colorscheme = 'solarized'
+    call lightline#init()
+    call lightline#colorscheme()
+    call lightline#update()
+  else
+    set background=dark
+    let g:lightline.colorscheme = 'seoul256'
+    call lightline#init()
+    call lightline#colorscheme()
+    call lightline#update()
+  endif
+endfunction
+
 augroup vimrc
   autocmd!
   " Automatically load/save views on files.
@@ -122,6 +141,7 @@ map <c-t> <esc>:tabnew<cr>
 " Select just-pasted text:
 nnoremap <silent> <leader>0 `[v`]
 nnoremap <silent> <leader>1 :set relativenumber!<cr>
+nnoremap <silent> <leader>2 :call SwitchBackground()<cr>
 map <leader>m :marks<cr>
 map <leader>R :ALERename<cr>
 map <leader>v :vsplit<cr>