Fixed English tenses as reported by tldr-lint

pages/common/mkdir.md

@@ -2,10 +2,10 @@
 
 > Creates a directory.
 
-- Creates a directory in current folder or given path:
+- Create a directory in current folder or given path:
 
 `mkdir {{directory}}`
 
-- Creates directories recursively (useful for creating nested dirs):
+- Create directories recursively (useful for creating nested dirs):
 
 `mkdir -p {{path}}`