move prereq sentence to last in get --show-url option

per #936 (review)

public/static/docs/command-reference/get.md

@@ -64,9 +64,9 @@ name.
   the file or directory from. The tip of the default branch is used by default
   when this option is not specified.
 
-- `--show-url` - `path` is expected to represent a cached, DVC-tracked file for
-  this option to have an effect. Instead of downloading the file or directory,
-  just print the storage location (URL) of the target data.
+- `--show-url` - instead of downloading the file or directory, just print the
+  storage location (URL) of the target data. `path` is expected to represent a
+  cached, DVC-tracked file for this option to have an effect.
 
 - `-h`, `--help` - prints the usage/help message, and exit.