Revert "; Fix capitalization of F1..F12 keys in docs"

This reverts commit fe5b20410f.

This change was not correct; these are Lisp symbols that should be in
lower-case.  Problem reported by Mattias Engdegård <mattiase@acm.org>.

doc/emacs/custom.texi

@@ -2009,7 +2009,7 @@ Other cursor repositioning keys.
 @itemx @code{insertline}, @code{deleteline}, @code{insertchar}, @code{deletechar}
 Miscellaneous function keys.
 
-@item @code{F1}, @code{F2}, @dots{} @code{F35}
+@item @code{f1}, @code{f2}, @dots{} @code{f35}
 Numbered function keys (across the top of the keyboard).
 
 @item @code{kp-add}, @code{kp-subtract}, @code{kp-multiply}, @code{kp-divide}

doc/misc/edt.texi

@@ -524,7 +524,7 @@ So, after executing @samp{xmodmap .xmodmaprc}, a press of the physical
 @key{F12} key looks like a Num_Lock keypress to X@.  Also, a press of the
 physical @key{NumLock} key looks like a press of the @key{F12} key to X.
 
-Now, @file{edt-mapper.el} will see @samp{F12} when the physical
+Now, @file{edt-mapper.el} will see @samp{f12} when the physical
 @key{NumLock} key is pressed, allowing the @key{NumLock} key to be used
 as the EDT @key{PF1} (@key{GOLD}) key.
 

doc/misc/idlwave.texi

@@ -3259,10 +3259,10 @@ Both functions take a single string argument sharing the syntax of the
                                         "help,___,/STRUCTURE"))))
 @end lisp
 
-@noindent Now pressing @key{F9}, or middle-mouse dragging with the
+@noindent Now pressing @key{f9}, or middle-mouse dragging with the
 @key{SUPER} key depressed, will print the dimensions of the nearby or
-highlighted expression.  Pressing @key{F10} will give the type string,
-and @key{F11} will show the contents of a nearby structure.  As you can
+highlighted expression.  Pressing @key{f10} will give the type string,
+and @key{f11} will show the contents of a nearby structure.  As you can
 see, the possibilities are only marginally finite.
 
 @defopt idlwave-shell-examine-alist

doc/misc/viper.texi

@@ -1142,7 +1142,7 @@ either by calling
 @end example
 
 @noindent
-or by setting @code{viper-buffer-search-char} to, say, @kbd{F3}:
+or by setting @code{viper-buffer-search-char} to, say, @kbd{f3}:
 @example
 (setq viper-buffer-search-char ?g)
 @end example
@@ -2763,7 +2763,7 @@ Second, Viper macros are defined in a WYSIWYG style.  This means that
 commands are executed as you type them, so you can see precisely what is
 being defined.  Third, macros can be bound to arbitrary sequences of keys,
 not just to printable keys.  For instance, one can define a macro that will
-be invoked by hitting @kbd{F3} then @kbd{F2} function keys.  (The keys
+be invoked by hitting @kbd{f3} then @kbd{f2} function keys.  (The keys
 @kbd{delete} and @kbd{backspace} are excluded; also, a macro invocation
 sequence can't start with @key{ESC}.  Some other keys, such as @kbd{f1} and
 @kbd{help}, can't be bound to macros under Emacs, since they
@@ -2816,7 +2816,7 @@ To do the same for Vi state and all buffers with the major mode
 Both macro names and macro definitions are vectors of symbols that denote
 keys on the keyboard.  Some keys, like @kbd{\}, @kbd{ }, or digit-keys must
 be escaped with a backslash.  Modified keys are represented as lists.  For
-instance, holding Meta and Control and pressing @kbd{F4} is represented as
+instance, holding Meta and Control and pressing @kbd{f4} is represented as
 @kbd{(control meta f4)}.
 If all members of a vectors are printable characters (or sequences, such as
 @kbd{\e}, @kbd{\t}, for @key{ESC} and @key{TAB}), then they can also be represented as
@@ -2915,7 +2915,7 @@ in that file:
 
 To illustrate the above point, Viper provides two canned macros, which, by
 default, are bound to @kbd{[f12 \1]} and @kbd{[f12 \2]} (invoked by typing
-@kbd{F12} then @kbd{1} and @kbd{2}, respectively).  These macros are useful
+@kbd{f12} then @kbd{1} and @kbd{2}, respectively).  These macros are useful
 shortcuts to Viper's command ring history.  The first macro will execute the
 second-last destructive command (the last one is executed by @kbd{.}, as
 usual).  The second macro executes the third-last command.
@@ -2931,7 +2931,7 @@ say, @kbd{f12 \3} like this:
 @end example
 
 
-Note that even though the macro uses the function key @kbd{F12}, the key is
+Note that even though the macro uses the function key @kbd{f12}, the key is
 actually free and can still be bound to some Emacs function via
 @code{define-key} or @code{global-set-key}.
 
@@ -2950,7 +2950,7 @@ twice and then the remaining keys, @kbd{t e x t}, will be processed.
 
 When defining macros using @kbd{:map} or @kbd{:map!}, the user enters
 the actually keys to be used to invoke the macro.  For instance, you
-should hit the actual key @kbd{F6} if it is to be part of a macro
+should hit the actual key @kbd{f6} if it is to be part of a macro
 name; you do @emph{not} write @kbd{f 6}.  When entering keys, Viper
 displays them as strings or vectors (e.g., @code{"abc"} or @code{[f6
 f7 a]}).  The same holds for unmapping.  Hitting @key{TAB} while