Make the 'history' and 'r' commands builtins (#76)

With this change no more preset aliases exist, so the preset alias
tables can be safely removed. All ksh commands can now be used
without 'unalias -a' removing them, even in interactive shells.
Additionally, the history and r commands are no longer limited to
being used in interactive shells.

src/cmd/ksh93/bltins/hist.c:
- Implement the history and r commands as builtins. Also guarantee
  lflag is set to one by avoiding 'lflag++'.

src/cmd/ksh93/Makefile,
src/cmd/ksh93/Mamfile,
src/cmd/ksh93/sh/main.c,
src/cmd/ksh93/sh/init.c,
src/cmd/ksh93/data/aliases.c:
- Remove the table of predefined aliases because the last few have
  been removed. During init the alias tree is now initialized the
  same way as the function tree.

src/cmd/ksh93/bltins/typeset.c:
- Remove the bugfix for unsetting predefined aliases because it is
  now a no-op. Aliases are no longer able to have the NV_NOFREE
  attribute.

src/cmd/ksh93/tests/alias.sh:
- Remove the regression test for unsetting predefined aliases since
  those no longer exist.

src/cmd/ksh93/data/builtins.c:
- Update sh_opthist[] for 'hist --man', etc.

src/cmd/ksh93/sh.1:
- Remove the list of preset aliases since those no longer exist.
- Document history and r as builtins instead of preset aliases.

Co-authored-by: Martijn Dekker <martijn@inlv.org>

src/cmd/ksh93/sh.1

@@ -777,20 +777,9 @@ not while they are executed.
 Therefore,
 for an alias to take effect,
 the
-.B
-alias
+.B alias
 definition command has to be executed before
 the command which references the alias is read.
-.PP
-The following aliases
-are compiled into the shell
-but can be unset or redefined:
-.RS 20
-.PD 0
-.TP
-.B "history=\(fmhist \-l\(fm"
-.TP
-.B "r=\(fmhist \-s\(fm"
 .PD
 .RE
 .SS Tilde Substitution.
@@ -4367,9 +4356,9 @@ to re-execute the command.
 In this case a substitution parameter of the form
 \f2old\fP\f3=\fP\f2new\fP
 can be used to modify the command before execution.
-For example, with the preset alias
+For example, with the builtin
 .BR r ,
-which is aliased to
+which is functionally equivalent to
 .BR "\(fmhist \-s\(fm" ,
 typing
 `\f3r bad=good c\fP'
@@ -6211,6 +6200,11 @@ after the optional substitution
 \f2old\^\fP\f3=\fP\f2new\^\fP
 is performed.
 .TP
+\f3history\fP \*(OK \f3\-nr\^\fP \*(CK \*(OK \f2first\^\fP \*(OK \f2last\^\fP \*(CK \*(CK
+Lists commands in the history file.
+The same as
+.BR hist\ \-l .
+.TP
 \(dd \f3integer\fP \f2vname\fP\*(OK\f3=\fP\f2value\^\fP\*(CK .\|.\|.
 Declares each \f2vname\fP to be a long integer number.
 The same as
@@ -6624,6 +6618,11 @@ or
 on the command line
 determines which method is used.
 .TP
+\f3r\fP \*(OK \f2old\fP\f3\=\fP\f2new\^\fP \*(CK \*(OK \f2command\^\fP \*(CK
+Reexecutes a command in the history file.
+The same as
+.BR hist\ \-s .
+.TP
 \f3read\fP \*(OK \f3\-ACSprsv\^\fP \*(CK \*(OK \f3\-d\fP \f2delim \^\fP\*(CK \*(OK \f3\-n\fP \f2n \^\fP\*(CK \*(OK \*(OK \f3\-N\fP \f2n \^\fP\*(CK \*(OK \f3\-t\fP \f2timeout \^\fP\*(CK \*(OK \f3\-u\fP \f2unit \^\fP\*(CK \*(OK \f2vname\f3?\f2prompt\^\f1 \*(CK \*(OK \f2vname\^\fP .\|.\|. \*(CK
 The shell input mechanism.
 One line is read and