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/cmd/ksh93/COMPATIBILITY

@@ -34,7 +34,7 @@ omitted features that are completely upward compatible.
 	interpreted literally.  Now it is an ANSI-C string.  You
 	must quote the dollar sign to get the previous behavior.
 	Also, a $ in front of a " indicates that the string needs
-	to be translated for locales other than C or POSIX.  The $ 
+	to be translated for locales other than C or POSIX.  The $
 	is ignored in the C and POSIX locale.
 
 7.	With ksh-88, tilde expansion did not take place inside ${...}.
@@ -55,7 +55,7 @@ omitted features that are completely upward compatible.
 	in your PATH, and you have a program named test in your
 	directory, it will be executed when you type test; the
 	built-in version will be run at the point /bin is found
-	in your PATH. 
+	in your PATH.
 
 11.	Some undocumented combinations of argument passing to ksh
 	builtins no longer works since ksh-93 is getopts conforming
@@ -72,7 +72,7 @@ omitted features that are completely upward compatible.
 14.	If the file name following a redirection symbol contain pattern
 	characters they will only be expanded for interactive shells.
 
-15.	The arguments to a dot script will be restored when it completes. 
+15.	The arguments to a dot script will be restored when it completes.
 
 16.	The list of tracked aliases is not displayed with alias unless
 	the -t option is specified.
@@ -85,7 +85,7 @@ omitted features that are completely upward compatible.
 18.	The ^T directive of emacs mode has been changed to work the
 	way it does in gnu-emacs.
 
-19.	ksh-88 allowed unbalanced parenthes within ${name op val} whereas
+19.	ksh-88 allowed unbalanced parentheses within ${name op val} whereas
 	ksh-93 does not.  Thus, ${foo-(} needs to be written as ${foo-\(}
 	which works with both versions.
 
@@ -100,7 +100,7 @@ omitted features that are completely upward compatible.
 	the end-of-options is reached to conform to the POSIX standard.
 
 23.	Since the POSIX standard requires that octal constants be
-	recongnized, doing arithmetic on typeset -Z variables can
+	recognized, doing arithmetic on typeset -Z variables can
 	yield different results that with ksh-88.  Most of these
 	differences were eliminated in ksh-93o.  Starting in ksh-93u+, the
 	let command no longer recognizes octal constants starting with 0
@@ -109,7 +109,7 @@ omitted features that are completely upward compatible.
 24.	Starting after ksh-93l, If you run ksh name, where name does
 	not contain a /, the current directory will be searched
 	before doing a path search on name as required by the POSIX
-	shell standard.  
+	shell standard.
 
 25.	In ksh-93, cd - will output the directory that it changes
 	to on standard output as required by X/Open.  With ksh-88,