docs: improve several plugin READMEs and add one for ssh plugin

plugins/aliases/README.md

@@ -1,7 +1,5 @@
 # Aliases cheatsheet
 
-**Maintainer:** [@hqingyi](https://github.com/hqingyi)
-
 With lots of 3rd-party amazing aliases installed, this plugin helps list the shortcuts
 that are currently available based on the plugins you have enabled.
 
@@ -13,6 +11,8 @@ plugins=(aliases)
 
 Requirements: Python needs to be installed.
 
+**Maintainer:** [@hqingyi](https://github.com/hqingyi)
+
 ## Usage
 
 - `als`: show all aliases by group