Fix various typos

Correct an assortment of typos throughout the code base.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net>
Closes #11774

lib/libzutil/zutil_import.c

@@ -1408,7 +1408,7 @@ discover_cached_paths(libpc_handle_t *hdl, nvlist_t *nv,
 
 	/*
 	 * Once we have the path, we need to add the directory to
-	 * our directoy cache.
+	 * our directory cache.
 	 */
 	if (nvlist_lookup_string(nv, ZPOOL_CONFIG_PATH, &path) == 0) {
 		return (zpool_find_import_scan_dir(hdl, lock, cache,