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/sh.1

@@ -800,7 +800,7 @@ is preceded by a tilde, then it is checked up to a
 .B /
 to see if it matches a user name in the
 password database (see
-.IR getpwname (3).)
+.IR getpwname (3)).
 If a match is found, the
 .B \(ap
 and the matched login name are replaced by the
@@ -1581,9 +1581,9 @@ the call to this function.
 Finally when
 .B _
 is used as the name of the first variable of a type definition,
-the new type is derived from the type of the first variable (See
+the new type is derived from the type of the first variable. (See
 .I "Type Variables"\^
-below.).
+below.)
 .TP
 .B !
 The process id or the pool name and job number of the last background command
@@ -5622,7 +5622,7 @@ reserved word syntax,
 the function is executed in the current environment
 (as if it had been defined with the
 .IB name ()
-syntax.)
+syntax).
 Otherwise if
 .I name\^
 refers to a file, the
@@ -6758,7 +6758,7 @@ or
 .B %f
 formats, separates groups of digits with the grouping delimiter
 .RB  ( ,
-on groups of 3 in the C locale.)
+on groups of 3 in the C locale).
 .PD
 .PP
 .RE