nvim: add config changes

* set diff, scroll, sidescroll, matching, ruler, folding and viminfo
  opts
* set up some fileformats
* properly check colour support

.config/nvim/init.vim

@@ -164,6 +164,33 @@ else
   set previewheight=5
 endif
 
+" filler lines to keep text position; start diff with vertical splits; don't
+" ignore case and whitespace changes
+set diffopt=filler,vertical
+
+" set scrolloff=3               " scroll offset, min lines above/below cursor
+set scrolloff=5               " scroll offset, min lines above/below cursor
+"set scrolljump=5             " jump 5 lines when running out of the screen - NO
+set sidescroll=10             " minimum columns to scroll horizontally
+" Make <,> match pairs, too.
+" https://github.com/EHartC/dot-vimrc/blob/master/vim%20config/styling.vim
+set matchpairs+=<:>
+set matchtime=2               " how many tenths of a second to blink when matching brackets
+set noshowmode                " show editing mode in status (-- INSERT --)
+set ruler                     " show cursor position
+
+" Tell vim to remember certain things when we exit
+"  '10  :  marks will be remembered for up to 10 previously edited files
+"  "100 :  will save up to 100 lines for each register
+"  :20  :  up to 20 lines of command-line history will be remembered
+"  %    :  saves and restores the buffer list
+set viminfo='100,"100,:20,%           " '=marks for x files, "=registers for x files
+
+" set nofoldenable
+set foldmethod=manual         " manual folding
+
+set fileencoding=utf-8        " set encoding for newly saved files
+set cmdheight=2               " lines under {status,air}line
 
 " colo dracula
 colo photon
@@ -194,10 +221,26 @@ set wildmode=longest:longest,full
 set colorcolumn=80
 filetype plugin indent on
 set hlsearch incsearch
+
 augroup filetypes
 	autocmd!
 	au BufRead,BufNewFile *.tmpl setlocal filetype=gohtmltmpl
 	au FileType gohtmltmpl setlocal ff=unix ts=2 shiftwidth=2 sts=2 noexpandtab
+  au FileType nix setl
+      \ fileformat=unix autoindent omnifunc=lsp#complete
+  au BufNewFile,BufRead,BufEnter *.js
+      \ setlocal shiftwidth=2 tabstop=2 softtabstop=2 backspace=2 expandtab autoindent
+      \ fileformat=unix filetype=javascript
+
+  au BufNewFile,BufRead,BufEnter *.md
+      \ setlocal textwidth=79 foldmethod=manual filetype=markdown
+      \ fileformat=unix expandtab
+
+  au FileType swayconfig setl textwidth=99
+      \ tabstop=4 shiftwidth=4 softtabstop=4 noexpandtab autoindent ft=swayconfig
+
+  au FileType rust setl
+      \ tabstop=8 shiftwidth=8 softtabstop=8 noexpandtab autoindent ff=unix
 augroup END
 
 
@@ -431,8 +474,11 @@ set noscrollbind
 set noerrorbells
 set laststatus=2                " show status bar
 set report=1                    " Always report number of lines changed by ex commands
-set termguicolors
-set t_Co=256
+if (has('termguicolors'))
+  set termguicolors
+else
+  set t_Co=256
+endif
 set guifont=Fira\ Code\ weight=450\ 12
 
 let g:netrw_beval = 1
@@ -472,6 +518,7 @@ for s in ['Comment', 'markdownItalic', 'Boolean']
 endfor
 hi CursorLineNR cterm=bold
 
+
 lua <<EOF
 require('nvim-highlight-colors').setup {enable_tailwind = true}
 
@@ -506,6 +553,7 @@ lspconfig.zls.setup {}
 
 lspconfig.golangci_lint.setup {}
 lspconfig.golangci_lint_ls.setup {}
+-- https://go.googlesource.com/tools/+/refs/heads/master/gopls/doc/vim.md
 lspconfig.gopls.setup{
   cmd = {"gopls", "-remote=unix;/tmp/.gopls-daemon.sock"},
 	filetypes = {"go", "gomod", "gowork", "gotmpl", "gohtmltmpl"},