(DOCSP-10960): Autocompletion instructions (#125)

* (DOCSP-10960): Autocompletion instructions

* updates per copy review

Author: jeff-allen-mongo

source/configure.txt

@@ -19,6 +19,7 @@ Configure the {+mcli+}
 
       /configure/configuration-file
       /configure/environment-variables
+      /configure/autocomplete
 
 You can define the settings that the {+mcli+} uses to interact with
 MongoDB services like |service|, |cloud-short|, and |onprem| by using

source/configure/autocomplete.txt

@@ -0,0 +1,122 @@
+.. _mcli-autocomplete:
+
+=======================================
+Enable Autocomplete for the {+mcli+}
+=======================================
+
+.. default-domain:: mongodb
+
+.. contents:: On this page
+   :local:
+   :backlinks: none
+   :depth: 1
+   :class: singlecol
+
+You can enable autocomplete for {+mcli+} commands to see available
+commands and their syntax directly in your shell.
+
+Enable Autocomplete
+-------------------
+
+.. tabs::
+
+   .. tab:: Homebrew Installation 
+      :tabid: Homebrew
+
+      If you installed the {+mcli+} with Homebrew, autocomplete
+      functionality is included with the installation. You must
+      configure your shell to enable its completion support. To enable
+      autocomplete for your shell, refer to the
+      `Homebrew Documentation
+      <https://docs.brew.sh/Shell-Completion>`__.
+
+   .. tab:: Other Installation
+      :tabid: non-Homebrew
+
+      If you did not install the {+mcli+} with Homebrew, the procedure
+      to enable autocomplete depends on the shell in which you
+      run the {+mcli+}.
+      
+      Z Shell
+      ~~~~~~~
+
+      If you use ``zsh`` to run the {+mcli+}, add the following to your
+      ``~/.zshrc``:
+
+      .. code-block:: sh
+
+         autoload -Uz compinit
+         compinit
+
+         source <(mongocli completion zsh)
+         compdef _mongocli mongocli
+
+      Run the following command to reload your ``zsh`` profile:
+
+      .. code-block:: sh
+
+         source ~/.zshrc
+
+      Bash
+      ~~~~
+
+      If you use Bash to run the {+mcli+}, add the following to your
+      ``~/.bash_profile``:
+
+      .. code-block:: sh
+
+         eval "$(mongocli completion bash)"
+
+      Run the following command to reload your Bash profile:
+
+      .. code-block:: sh
+
+         source ~/.bash_profile
+
+Use ``Tab`` to Autocomplete Commands
+------------------------------------
+
+Once you have autocomplete configured, you can autocomplete commands by
+typing ``mongocli`` in your shell and pressing the ``Tab`` key. Press
+``Tab`` multiple times to cycle through available autocompletion
+options.
+
+You can press ``Tab`` at any stage of writing your command to see
+available autocomplete options.
+
+Examples
+~~~~~~~~
+
+When you type ``mongocli`` in your shell and press ``Tab``, the output
+resembles the following:
+
+.. code-block:: none
+   :copyable: false
+
+   atlas          -- Atlas operations.
+   cloud-manager  -- Cloud Manager operations.
+   completion     -- Generate shell completion scripts
+   config         -- Configure a profile to store access settings for your MongoDB deployment.
+   help           -- Help about any command
+   iam            -- Organization and projects operations.
+   ops-manager    -- Ops Manager operations.
+
+If you type a specific property such as ``atlas`` as part of your
+command, you can see autocompletion options for your selected
+property.
+
+For example, when you type ``mongocli atlas`` in your shell and press
+``Tab``, the output resembles the following:
+
+.. code-block:: none
+   :copyable: false
+
+   alerts     -- Manage alerts for your project.
+   backups    -- Manage backups for your project.
+   clusters   -- Manage clusters for your project.
+   dbusers    -- Manage database users for your project.
+   events     -- Manage events for your project.
+   logs       -- Download host logs for your project.
+   metrics    -- Get measurements on the state of the MongoDB process.
+   processes  -- Manage MongoDB processes for your project.
+   whitelist  -- Manage the IP whitelist for a project.