git-fetch: add --prune and bare example (#1189)

pages/common/git-fetch.md

@@ -2,14 +2,22 @@
 
 > Download objects and refs from a remote repository.
 
-- Fetch new branches from upstream, and update local remote-tracking branches:
+- Fetch the latest changes from the default remote upstream repository (if set):
+
+`git fetch`
+
+- Fetch new branches from a specific remote upstream repository:
 
 `git fetch {{remote_name}}`
 
-- Fetch the latest changes from all remote git servers:
+- Fetch the latest changes from all remote upstream repositories:
 
 `git fetch --all`
 
-- Also fetch tags from the remote repository:
+- Also fetch tags from the remote upstream repository:
 
 `git fetch --tags`
+
+- Delete local remote-tracking branches that have been deleted upstream:
+
+`git fetch --prune`