website/docs: document `vagrant rsync`

website/docs/source/v2/cli/non-primary.html.md

@@ -17,3 +17,8 @@ Note that while you have to run a special command to list the non-primary
 subcommands, you don't have to do anything special to actually _run_ the
 non-primary subcommands. They're executed just like any other subcommand:
 `vagrant COMMAND`.
+
+The list of non-primary commands is below. Click on any command to learn
+more about it.
+
+* [rsync](/v2/cli/rsync.html)

website/docs/source/v2/cli/rsync.html.md

@@ -0,0 +1,11 @@
+---
+page_title: "vagrant rsync - Command-Line Interface"
+sidebar_current: "cli-rsync"
+---
+
+# Rsync
+
+**Command: `vagrant rsync`**
+
+This command forces a resync of any
+[rsync synced folders](/v2/synced-folders/rsync.html).

website/docs/source/v2/synced-folders/rsync.html.md

@@ -44,7 +44,6 @@ end
 
 ## Re-Syncing
 
-The rsync sync is done only during a `vagrant up` or `vagrant reload`. It
-is not currently possible to force a re-sync in any way other than reloading.
-
-We plan on exposing a command to force a sync in a future version of Vagrant.
+The rsync sync is done only during a `vagrant up` or `vagrant reload`. Vagrant
+does not automatically listen for changes on the filesystem and resync them.
+Resyncing can be forced with a call to [vagrant rsync](/v2/cli/rsync.html).