[nvim] Add peekaboo plugin to display registers

nvim/.config/nvim/plugin/vim-peekaboo.vim

@@ -0,0 +1,31 @@
+" PLUGIN: vim-peekaboo
+let g:peekaboo_delay=500
+
+function! CreateCenteredFloatingWindow()
+  let width = float2nr(&columns * 0.6)
+  let height = float2nr(&lines * 0.6)
+  let top = ((&lines - height) / 2) - 1
+  let left = (&columns - width) / 2
+  let opts = {'relative': 'editor', 'row': top, 'col': left, 'width': width, 'height': height, 'style': 'minimal'}
+
+  let top = "╭" . repeat("─", width - 2) . "╮"
+  let mid = "│" . repeat(" ", width - 2) . "│"
+  let bot = "╰" . repeat("─", width - 2) . "╯"
+  let lines = [top] + repeat([mid], height - 2) + [bot]
+  let s:buf = nvim_create_buf(v:false, v:true)
+  call nvim_buf_set_lines(s:buf, 0, -1, v:true, lines)
+  call nvim_open_win(s:buf, v:true, opts)
+  set winhl=Normal:Floating
+  let opts.row += 1
+  let opts.height -= 2
+  let opts.col += 2
+  let opts.width -= 4
+  call nvim_open_win(nvim_create_buf(v:false, v:true), v:true, opts)
+  au BufWipeout <buffer> exe 'bw '.s:buf
+endfunction
+
+if has('nvim-0.4.0') || has("patch-8.2.0191")
+    let g:peekaboo_window = "call CreateCenteredFloatingWindow()"
+else " Fallback to a split window
+    let g:peekaboo_window={"window": "vert bo 30new"}
+endif