docs: fix markdown lint issues in command docs

cmd/ls/ls.go

@@ -21,13 +21,15 @@ var commandDefinition = &cobra.Command{
 	Long: `Lists the objects in the source path to standard output in a human
 readable format with size and path. Recurses by default.
 
-Eg
+E.g.
 
-    $ rclone ls swift:bucket
-        60295 bevajer5jef
-        90613 canole
-        94467 diwogej7
-        37600 fubuwic
+` + "```sh" + `
+$ rclone ls swift:bucket
+    60295 bevajer5jef
+    90613 canole
+    94467 diwogej7
+    37600 fubuwic
+` + "```" + `
 
 ` + lshelp.Help,
 	Annotations: map[string]string{