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/tm.3

@@ -46,7 +46,7 @@ The
 .I tm
 library supports conversion between
 string date specifications,
-seconds reolution
+seconds resolution
 .L time_t
 clock values and
 .LR Tm_t .
@@ -356,7 +356,7 @@ The nanosecond part of the time.
 \fB%Q\fP\fI<delim>recent<delim>distant<delim>\fP
 Recent dates are formatted with
 .I recent
-and distand dates are formatted with
+and distant dates are formatted with
 .IR distant ,
 where
 .I <delim>
@@ -400,7 +400,7 @@ character.
 .IR hh : mm : ss .
 .TP
 .B u
-Weeday number with 1 for Monday, 7 for Sunday.
+Weekday number with 1 for Monday, 7 for Sunday.
 .TP
 .B U
 Week number with Sunday as the first day.
@@ -507,9 +507,9 @@ then it specifies a time zone other that the local time zone.
 .TP
 .L "void tmset(Tm_zone_t* zone);"
 .L tmset
-sets the reference timezoe to
+sets the reference timezone to
 .LR zone .
-.L tm_info.local 
+.L tm_info.local
 points to the local timezone and
 .L tm_info.zone
 points to the current reference timezone.