feat: add the paste functionality into the ivy prompt

Now when you paste and you are in an ivy buffer the paste will be added
to the prompt not into the completion window. You can use your usual
paste key binding I.E. <SHIFT>+<INSERT> <CTRL>+<SHIFT>+<V>

Ref: #11

lua/ivy/controller.lua

@@ -30,6 +30,10 @@ controller.search = function(value)
   controller.update(prompt.text())
 end
 
+controller.paste = function()
+  controller.search(prompt.text() .. vim.fn.getreg "+p")
+end
+
 controller.update = function(text)
   vim.schedule(function()
     window.set_items(controller.items(text))

plugin/ivy.lua

@@ -25,7 +25,17 @@ local register_backend = function(backend)
   end
 end
 
-register_backend(require "ivy.backends.ag")
+vim.paste = (function(overridden)
+  return function(lines, phase)
+    local file_type = vim.api.nvim_buf_get_option(0, "filetype")
+    if file_type == "ivy" then
+      vim.ivy.paste()
+    else
+      overridden(lines, phase)
+    end
+  end
+end)(vim.paste)
+
 register_backend(require "ivy.backends.buffers")
 register_backend(require "ivy.backends.files")
 register_backend(require "ivy.backends.lines")