Implement 'winhl' user option

README.md

@@ -2,6 +2,10 @@
 Show where your cursor moves when jumping large distances (e.g between windows). Fast and lightweight, written completely in Lua. WIP.
 
 ![demo](https://user-images.githubusercontent.com/28115337/111098526-90923e00-853b-11eb-8e7c-c5892d64c180.gif)
+
+New: added option for custom highlighting for popup:
+![demo2](https://user-images.githubusercontent.com/28115337/112231882-7b01d000-8c2f-11eb-9f06-e6e6e492a533.gif)
+
 ## Install
 Using [packer.nvim](https://github.com/wbthomason/packer.nvim):
 ```lua
@@ -22,6 +26,7 @@ require('specs').setup{
         inc_ms = 10,
         blend = 10,
         width = 10,
+        winhl = "PMenu",
         fader = require('specs').linear_fader,
         resizer = require('specs').shrink_resizer
     }

lua/specs/init.lua

@@ -26,8 +26,11 @@ function M.show_specs()
         row = cursor_row,
         style = 'minimal'
     })
+    vim.api.nvim_win_set_option(win_id, 'winhl', 'Normal:'.. opts.popup.winhl)
     vim.api.nvim_win_set_option(win_id, "winblend", opts.popup.blend)
 
+    
+
     local cnt = 0
     local config = vim.api.nvim_win_get_config(win_id)
     local timer = vim.loop.new_timer()
@@ -123,6 +126,7 @@ local DEFAULT_OPTS = {
         inc_ms = 5,
         blend = 10,
         width = 20,
+        winhl = "PMenu",
         fader = M.exp_fader,
         resizer = M.shrink_resizer
     }