Document some new user options

* eat.texi (Semi-char Mode): Document
'eat-semi-char-non-bound-keys' and
'eat-eshell-semi-char-non-bound-keys'.
* eat.texi (Input Invisible): New section.

eat.el

@@ -166,8 +166,8 @@ Keys appearing in this list are not bound to send the key to terminal.
 Eat might still bound them to do something else (for example, changing
 keybinding mode).
 
-Each element is a vector of form [KEY] or [?\e KEY], meaning KEY or
+Each element is a vector of form [KEY] or [?\\e KEY], meaning KEY or
-M-KEY shouldn't be bound.  KEY shouldn't contain Meta (Alt) modifier."
+M-KEY shouldn't be bound.  KEY shouldn't contain meta (Alt) modifier."
   :type '(repeat sexp)
   :set (lambda (sym val)
          (set-default-toplevel-value sym val)
@@ -185,8 +185,8 @@ Keys appearing in this list are not bound to send the key to terminal.
 Eat might still bound them to do something else (for example, changing
 keybinding mode).
 
-Each element is a vector of form [KEY] or [?\e KEY], meaning KEY or
+Each element is a vector of form [KEY] or [?\\e KEY], meaning KEY or
-M-KEY shouldn't be bound.  KEY shouldn't contain Meta (Alt) modifier."
+M-KEY shouldn't be bound.  KEY shouldn't contain meta (Alt) modifier."
   :type '(repeat sexp)
   :set (lambda (sym val)
          (set-default-toplevel-value sym val)

eat.texi

@@ -100,7 +100,7 @@ emulators.  But it has some key features that make Eat distinct from
 other terminal emulators.
 
 Firstly, it's in Emacs, which means you don't need to leave the
-comfort of Emacs to use Emacs.
+comfort of Emacs to use terminal.
 
 Secondly, it's easy and convenient to use.  It is tries to stay out of
 your way, allowing you to maximize your productivity.
@@ -268,6 +268,32 @@ Emacs built-in terminal emulator, you can still input any character.
 In ``semi-char mode'', @kbd{C-c C-c} sends a @kbd{C-c}, just for
 convenience, and @kbd{C-c C-k} kills the terminal program.
 
+@cindex customizing semi-char mode
+@cindex customizing semi-char mode keys
+@cindex customizing semi-char mode keybindings
+@cindex mode, semi-char, customizing
+@cindex keybindings, semi-char mode, customizing
+@cindex keybinding mode, semi-char, customizing
+@cindex input mode, semi-char, customizing
+@cindex mode, semi-char, adding exceptions
+@cindex keybindings, semi-char mode, adding exceptions
+@cindex keybinding mode, semi-char, adding exceptions
+@cindex input mode, semi-char, adding exceptions
+@cindex mode, semi-char, exception, add
+@cindex keybindings, semi-char mode, exception, add
+@cindex keybinding mode, semi-char, exception, add
+@cindex input mode, semi-char, exception, add
+@vindex eat-semi-char-non-bound-keys
+@vindex eat-eshell-semi-char-non-bound-keys
+You can customize the exceptions by customizing the user option
+@code{eat-semi-char-non-bound-keys}, and
+@code{eat-eshell-semi-char-non-bound-keys} for Eshell integration.
+Both user options contain a list of keys of form @code{[@var{key}]},
+where @var{key} is a key not to bind.  @var{key} mustn't contain meta
+modifier.  To not bind a key with meta modifier, use a vector of form
+@code{[?\e @var{key}]}, where @var{key} is the key without meta
+modifier.
+
 @anchor{Char Mode}
 @cindex char mode
 @cindex mode, char
@@ -862,6 +888,7 @@ Eat does something unexpected, such as hangs, garbled text, etc.
 @menu
 * Not Recognized::      The program can't recognize Eat.
 * Garbled Text::        When you get garbage on your terminal.
+* Input Invisible::     The input is not shown.
 * Not Responding::      What to do if Eat is unresponsive.
 * Signaled an Error::   The worst and the most unlikely bug.
 * Bugs in Manual::      What if there are problems in this manual?
@@ -903,7 +930,7 @@ If the text on the terminal looks wrong, first check out the value of
 send invalid escape sequences.
 
 First, @pxref{Not Recognized}; the problem is most likely because the
-problem doesn't recognize Eat, and it stays silent instead of
+program doesn't recognize Eat, and it stays silent instead of
 reporting that.
 
 If the problem isn't resolved after following the instructions in the
@@ -917,6 +944,26 @@ feature request.
 The other potential reason is that Eat is not working.  This is
 definitely a bug, so please report it.
 
+@node Input Invisible
+@cindex input invisible
+@cindex input, invisible
+@cindex invisible input
+@cindex invisible, input
+@section Input Invisible
+
+This can happen if the @samp{stty} program is unavailable on the
+system.  Eat uses @samp{stty} to set various terminal settings
+including input echoing.  Please install the @samp{stty} program to
+fix the problem.
+
+@vindex eat-eshell-fallback-if-stty-not-available
+If you are using Eat from Eshell (@pxref{Eshell Terminal}), you might
+want to set @code{eat-eshell-fallback-if-stty-not-available} to handle
+such cases.  The user option can be set to three possible value,
+@code{t} to automatically fallback to bare Eshell when @samp{stty} is
+not available, @code{nil} to do nothing, and @samp{ask} to ask
+interactively.
+
 @node Not Responding
 @cindex not responding, eat
 @cindex not responding, emacs