Fix a large number of typos and other problems (#110)

Most of these fixes are for typos and extra whitespace at the
end of lines. These are the notable changes:
- Fixed a compatibility issue with how asterisks are displayed
  using certain fonts. Bug report: https://github.com/att/ast/issues/764
- Fixed a bug in the man page that caused searches for the '|'
  character to fail. Bug report: https://github.com/att/ast/issues/871
- Removed a duplicate description of 'set -B' from the man
  page. Bug report: https://github.com/att/ast/issues/789
- Added documentation for options missing from the ksh man
  page (applies to 'hist -N', 'sleep -s', 'whence -q' and
  many of ulimit's options). Bug reports:
  https://github.com/att/ast/issues/948
  https://github.com/att/ast/issues/503#issuecomment-386649715
  https://github.com/att/ast/issues/507#issuecomment-507924608
- Applied the following ksh2020 documentation fixes:
  https://github.com/att/ast/pull/351
  https://github.com/att/ast/pull/352
- Fixed a minor GCC -Wformat warning in procopen.c by changing
  a sentinel to NULL.

src/lib/libast/man/swap.3

@@ -60,7 +60,7 @@ and
 .PP
 .L swapop
 returns the swap operation required to convert the
-.L width 
+.L width
 byte integer
 .L external
 to the
@@ -85,7 +85,7 @@ and
 .L 1
 with bytes
 .L 2
-and 
+and
 .LR 3 .
 .TP
 .L 4
@@ -101,7 +101,7 @@ in the header
 described in
 .IR int (3).
 .PP
-.L swapget 
+.L swapget
 returns the
 .L width
 byte integer in the buffer
@@ -109,7 +109,7 @@ byte integer in the buffer
 swapped according to
 .LR op .
 .PP
-.L swapput 
+.L swapput
 copies the
 .L width
 byte integer
@@ -122,16 +122,16 @@ swapped according to
 is returned.
 .PP
 .L swapmem
-swaps 
+swaps
 .L n
 bytes from the buffer
 .L from
 to the buffer
 .L to
-according to 
+according to
 .LR op .
 .L to
-and 
+and
 .L from
 may be the same.
 .SH "SEE ALSO"