Lots of man page fixes and some other minor fixes (#284)

Noteworthy changes:
- The man pages have been updated to fix a ton of instances of
  runaway underlining (this was done with `sed -i 's/\\f5/\\f3/g'`
  commands). This commit dramatically increased in size because
  of this change.
- The documentation for spawnveg(3) has been extended with
  information about its usage of posix_spawn(3) and vfork(2).
- The documentation for tmfmt(3) has been updated with the changes
  previously made to the man pages for the printf and date builtins
  (though the latter builtin is disabled by default).
- The shell's tracked alias tree (hash table) is now documented in
  the shell(3) man page.
- Removed the commented out regression test for an ERRNO variable
  as the COMPATIBILITY file states it was removed in ksh93.

src/cmd/ksh93/tests/builtins.sh

@@ -280,7 +280,7 @@ if	[[ $(trap --version 2> /dev/null;print done) != done ]]
 then	err_exit 'trap builtin terminating after --version'
 fi
 if	[[ $(set --version 2> /dev/null;print done) != done ]]
-then	err_exit 'set builtin terminating after --veresion'
+then	err_exit 'set builtin terminating after --version'
 fi
 unset -f foobar
 function foobar
@@ -776,7 +776,7 @@ unset foo
 integer foo=1
 exp=4
 got=$(foo+=3 command eval 'echo $foo')
-[[ $exp == $got ]] || err_exit "[1]: += assignment for environment variables doesn't work with 'command special_builtin'" \
+[[ $exp == $got ]] || err_exit "Test 1: += assignment for environment variables doesn't work with 'command special_builtin'" \
 	"(expected $exp, got $got)"
 foo+=3 command eval 'test $foo'
 (( foo == 1 )) || err_exit "environment isn't restored after 'command special_builtin'" \
@@ -788,7 +788,7 @@ got=$(foo+=3 eval 'echo $foo')
 unset foo
 exp=barbaz
 got=$(foo=bar; foo+=baz command eval 'echo $foo')
-[[ $exp == $got ]] || err_exit "[2]: += assignment for environment variables doesn't work with 'command special_builtin'" \
+[[ $exp == $got ]] || err_exit "Test 2: += assignment for environment variables doesn't work with 'command special_builtin'" \
 	"(expected $exp, got $got)"
 
 # Attempting to modify a readonly variable with the += operator should fail

src/cmd/ksh93/tests/path.sh

@@ -878,8 +878,6 @@ got=$?
 	"(expected $exp, got $got)"
 
 # Tests for attempting to use a command name that's too long.
-# To make the error messages readable, the long string is replaced
-# with 'LONG_CMD_NAME' in the err_exit output.
 long_cmd=$(awk -v ORS= 'BEGIN { for(i=0;i<500;i++) print "xxxxxxxxxx"; }')
 exp=127
 PATH=$PWD $SHELL -c "$long_cmd" > /dev/null 2>&1

src/cmd/ksh93/tests/variables.sh

@@ -44,14 +44,6 @@ set abc def
 if	[[ $_ != def ]]
 then	err_exit _ variable not working
 fi
-# ERRNO
-#set abc def
-#rm -f foobar#
-#ERRNO=
-#2> /dev/null < foobar#
-#if	(( ERRNO == 0 ))
-#then	err_exit ERRNO variable not working
-#fi
 # PWD
 if	[[ !  $PWD -ef . ]]
 then	err_exit PWD variable failed, not equivalent to .