minor fix to Posix part of walkDir (#16234)
minor fix to Posix part of walkDir (#16234)

* change break->continue and rewrite one-yield-style

* use case statement for clarity

* Tiny nit

Co-authored-by: Clyybber <4759ea49cab7ee19e39bc4f5e544678ec18320f0@gmail.com>
dom96/Nim,dom96/Nim,dom96/Nim,dom96/Nim,dom96/Nim,dom96/Nim,dom96/Nim