Remove exps in remote git repo.

related to iterative/dvc#6471

content/docs/command-reference/exp/remove.md

@@ -5,7 +5,7 @@ Delete specific `dvc experiments` from the <abbr>project</abbr>.
 ## Synopsis
 
 ```usage
-usage: dvc exp remove [-h] [-q | -v] [--queue | -A]
+usage: dvc exp remove [-h] [-q | -v] [--queue | -A | -g <git_remote>]
                       [<name> [<name> ...]]
 
 positional arguments:
@@ -28,6 +28,9 @@ With `--queue`, the list of experiments awaiting execution is cleared instead.
 
 - `-A`, `--all` - remove all experiments (includes `--queue`).
 
+- `-g`, `--git-remote` - Name of the Git remote to GC all of the experiment
+  branches.
+
 - `-h`, `--help` - shows the help message and exit.
 
 - `-q`, `--quiet` - do not write anything to standard output. Exit with 0 if no