Add some documentation about plugin manager

runtime/help/commands.md

@@ -11,7 +11,7 @@ Here are the possible commands that you can use.
 * `replace "search" "value" flags`: This will replace `search` with `value`. 
    The `flags` are optional.
    At this point, there is only one flag: `c`, which enables `check` mode 
-   which asks if you'd like to perform the replacement each time
+   which asks if you'd like to perform the replacement each time.
 
    Note that `search` must be a valid regex.  If one of the arguments
    does not have any spaces in it, you may omit the quotes.
@@ -35,14 +35,29 @@ Here are the possible commands that you can use.
    keybindings above for more info about what keys and actions are available.
 
 * `vsplit filename`: opens a vertical split with `filename`. If no filename is
-   provided, a vertical split is opened with an empty buffer
+   provided, a vertical split is opened with an empty buffer.
 
 * `hsplit filename`: same as `vsplit` but opens a horizontal split instead of
-   a vertical split
+   a vertical split.
 
 * `tab filename`: opens the given file in a new tab.
 
-* `log`: opens a log of all messages and debug statements
+* `log`: opens a log of all messages and debug statements.
+
+* `plugin install plugin_name`: installs the given plugin.
+
+* `plugin remove plugin_name`: removes the given plugin.
+
+* `plugin list`: lists all installed plugins.
+
+* `plugin update`: updates all installed plugins.
+
+* `plugin search plugin_name`: searches for the given plugin.
+   Note that you can find a list of all available plugins at
+   github.com/micro-editor/plugin-channel.
+
+   You can also see more information about the plugin manager
+   in the `Plugin Manager` section of the `plugins` help topic.
 
 ---