feat(previewer): add option for ls --short (#2486)

Co-authored-by: Github Actions <actions@github>

doc/telescope.txt

@@ -523,6 +523,10 @@ telescope.setup({opts})                                    *telescope.setup()*
           - hide_on_startup:  Hide previewer when picker starts. Previewer can be toggled
                               with actions.layout.toggle_preview.
                               Default: false
+          - ls_short:         Determines whether to use the `--short` flag for the `ls`
+                              command when previewing directories. Otherwise will result
+                              to using `--long`.
+                              Default: false
 
 
                                      *telescope.defaults.vimgrep_arguments*