Base: Add more manpages for command-line utilities

Base/usr/share/man/man1/yes.md

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+## Name
+
+yes - output a string repeatedly until killed
+
+## Synopsis
+
+```**sh
+$ yes [string]
+```
+
+## Description
+
+`yes` outputs an endless stream of specified `string` (with trailing newline) in a loop.
+
+## Options
+
+* `string`: String to print; defaults to "yes".
+
+## Examples
+
+```sh
+$ yes
+yes
+yes
+yes
+yes
+yes
+yes
+yes^C
+$ yes t
+t
+t
+t
+t
+t
+t
+t
+t
+t
+t^C
+```