feat: prompt_prefix option (#154)

* enable prompt_prefix option

* add hl and default value

* default hl and prefix

* fixup: move the redraw til after prompt create

* fixup: nits

Co-authored-by: TJ DeVries <devries.timothyj@gmail.com>

lua/telescope/config.lua

@@ -46,6 +46,8 @@ function config.set_defaults(defaults)
   set("results_height", 1)
   set("results_width", 0.8)
 
+  set("prompt_prefix", " > ")
+
   set("border", {})
   set("borderchars", { '─', '│', '─', '│', '╭', '╮', '╯', '╰'})