eshell.texi improvements

* doc/misc/eshell.texi (Built-ins): eshell/sudo is a compiled
Lisp function in `em-tramp.el'.  Mention also $*, $1, $2, ...
(Aliases): Add $*, $1, $2, ... to the variable index.

doc/misc/eshell.texi

@@ -239,7 +239,6 @@ especially for file names with special characters like pipe
 (@code{|}), which could be part of remote file names.
 
 @node Built-ins
-
 @section Built-in commands
 Several commands are built-in in Eshell.  In order to call the
 external variant of a built-in command @code{foo}, you could call
@@ -258,7 +257,7 @@ alias, @ref{Aliases}.  Example:
 
 @example
 ~ $ which sudo
-eshell/sudo is a compiled Lisp function in `em-unix.el'
+eshell/sudo is a compiled Lisp function in `em-tramp.el'.
 ~ $ alias sudo '*sudo $*'
 ~ $ which sudo
 sudo is an alias, defined as "*sudo $*"
@@ -419,6 +418,9 @@ Lisp functions, based on successful completion).
 
 @end table
 
+@ref{Aliases} for the built-in variables @samp{$*}, @samp{$1},
+@samp{$2}, @dots{}, in alias definitions.
+
 @node Variables
 @section Variables
 Since Eshell is just an Emacs REPL@footnote{Read-Eval-Print Loop}, it
@@ -429,6 +431,7 @@ would in an Elisp program.  Eshell provides a command version of
 @node Aliases
 @section Aliases
 
+@vindex $*
 Aliases are commands that expand to a longer input line.  For example,
 @command{ll} is a common alias for @code{ls -l}, and would be defined
 with the command invocation @kbd{alias ll 'ls -l $*'}; with this defined,
@@ -438,6 +441,7 @@ automatically written to the file named by @code{eshell-aliases-file},
 which you can also edit directly (although you will have to manually
 reload it).
 
+@vindex $1, $2, @dots{}
 Note that unlike aliases in Bash, arguments must be handled
 explicitly.  Typically the alias definition would end in @samp{$*} to
 pass all arguments along.  More selective use of arguments via