* eshell.texi (Input/Output): Expand to cover new visual-command
options, eshell-visual-subcommands and eshell-visual-options.
Divide into separate Visual Commands and Redirection sections.
* eshell/em-term.el (eshell-visual-commands)
(eshell-visual-subcommands)
(eshell-visual-options): Add summary line to docstrings. Add
cross-references.