mention yash

Author: mirabilos

posix/0-README

@@ -1,5 +1,6 @@
 Shell snippets that run with a POSIX shell.
-GNU bash, dash, AT&T ksh93, mksh. Maybe pdksh, posh, zsh in “emulate sh” mode.
+GNU bash, dash, AT&T ksh93, mksh, yash.
+Maybe pdksh, posh, zsh in “emulate sh” mode.
 
 Some snippets assume that functions can have local variables;
 those won’t work with AT&T ksh but any /bin/sh in Debian (Policy §10.4).