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/chr.3

@@ -57,7 +57,7 @@ is not 0 then
 is set to point to the next character in
 .I s
 on return.
-0 is returned and 
+0 is returned and
 .I e
 is not modified when the end of
 .I s
@@ -77,9 +77,9 @@ value until up to the number of characters in an
 .I int
 is reached.
 This operation is inherently machine-dependent,
-but at least its defined in one place.
+but at least it's defined in one place.
 .PP
-The following 
+The following
 .B \e
 escape sequences are recognized:
 .TP