feat: Add normal mode operator (Luadev-RunOperator)

The logic is abstracted into the s:luadev_run_operator function that
receives the first parameter "visual" to know it should use the visual
range. Otherwise work with motions. In this case motions that expand
over one line execute code linewise from the start to the end. This
makes motions j,k,%,/,? be more ergonomic I believe.

plugin/luadev.vim

@@ -1,23 +1,47 @@
 command! Luadev lua require'luadev'.start()
 
 noremap <Plug>(Luadev-RunLine) <Cmd>lua require'luadev'.exec(vim.api.nvim_get_current_line())<cr>
-vnoremap <silent> <Plug>(Luadev-Run) :<c-u>call luaeval("require'luadev'.exec(_A)", <SID>get_visual_selection())<cr>
+vnoremap <silent> <Plug>(Luadev-Run) :<c-u>call <SID>luadev_run_operator('visual')<cr>
+noremap <silent> <Plug>(Luadev-RunOperator) :<c-u>set opfunc=<SID>luadev_run_operator<cr>g@
 noremap <silent> <Plug>(Luadev-RunWord) :<c-u>call luaeval("require'luadev'.exec(_A)", <SID>get_current_word())<cr>
 inoremap <Plug>(Luadev-Complete) <Cmd>lua require'luadev.complete'()<cr>
 
+
 " thanks to @xolox on stackoverflow
-function! s:get_visual_selection()
-    let [lnum1, col1] = getpos("'<")[1:2]
-    let [lnum2, col2] = getpos("'>")[1:2]
+" same function for visual and normal. Except visual passes a parameter.
+function! s:luadev_run_operator(type = '')
+    if a:type == "visual"
+        let mode = "visual"
+    else
+        let mode = "normal"
+    end
+
+    if mode == 'visual'
+        let [lnum1, col1] = getpos("'<")[1:2]
+        let [lnum2, col2] = getpos("'>")[1:2]
+    elseif mode == 'normal'
+        let [lnum1, col1] = getpos("'[")[1:2]
+        let [lnum2, col2] = getpos("']")[1:2]
+    endif
 
     if lnum1 > lnum2
       let [lnum1, col1, lnum2, col2] = [lnum2, col2, lnum1, col1]
     endif
 
+    " Normal motions that are more than one line are forced to linewise
+    if lnum1 != lnum2 && mode =="normal"
+        let linewise = v:true
+    else
+        let linewise = v:false
+    end
+
     let lines = getline(lnum1, lnum2)
-    let lines[-1] = lines[-1][: col2 - (&selection == 'inclusive' ? 1 : 2)]
-    let lines[0] = lines[0][col1 - 1:]
-    return join(lines, "\n")."\n"
+    if linewise == v:false
+        let lines[-1] = lines[-1][: col2 - (&selection == 'inclusive' ? 1 : 2)]
+        let lines[0] = lines[0][col1 - 1:]
+    end
+    let lines =  join(lines, "\n")."\n"
+    call luaeval("require'luadev'.exec(_A)", lines)
 endfunction
 
 function! s:get_current_word()