Start documenting the choose-files kitten

Author: kovidgoyal

docs/kittens/choose-files.rst

@@ -6,6 +6,25 @@ Selecting files, fast
     Overview
     --------------
 
+.. versionadded:: 0.43.0
+
+The choose-files kitten is designed to allow you to select files, very fast,
+with just a few key strokes. It operates like `fzf
+<https://github.com/junegunn/fzf/>`__ and similar fuzzy finders, except that
+it is specialised for finding files. As such it supports features such as
+filtering by file type, file type icons, content previews (coming soon) and
+so on, out of the box. It can be used as a drop in (but much more efficient and
+keyboard friendly) replacement for the :guilabel:`File open and save`
+dialog boxes common to GUI programs. On Linux, with the help of the
+:doc:`desktop-ui </kittens/desktop-ui>` kitten, you can even convince
+most GUI programs on your computer to use this kitten instead of regular file
+dialogs.
+
+Simply run it as::
+
+    kitten choose-files
+
+to select a single file from the tree rooted at the current working directory.
 
 Configuration
 ------------------------

kittens/choose_files/main.py

@@ -149,6 +149,10 @@ def main(args: list[str]) -> None:
 
 
 help_text = '''\
+Select one or more files, quickly, using fuzzy finding, by typing just a few characters from
+the file name. Browse matching files, using the arrow keys to navigate matches and press :kbd:`Enter`
+to select. The :kbd:`Tab` key can be used to change to a sub-folder. See the :doc:`online docs </kittens/choose-files>`
+for full details.
 '''