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/vmalloc.3

@@ -53,7 +53,7 @@ vmalloc \- virtual memory allocation
 .MW "int vmstat(Vmalloc_t* vm, Vmstat_t* statb);"
 .MW "int vmtrace(int fd);"
 .MW "int vmtrbusy(Vmalloc_t* vm);"
-.MW "Void_t* vmdata(Vmalloc_t* vm);" 
+.MW "Void_t* vmdata(Vmalloc_t* vm);"
 .fi
 .SS "Malloc-compatible functions"
 .nf
@@ -268,7 +268,7 @@ a structure with these members:
 .fi
 .in -.5i
 .TP
-.MW round 
+.MW round
 If this value is positive, all size arguments to the
 \f5memoryf\fP function will be multiples of it.
 .TP
@@ -410,7 +410,7 @@ By default, this file descriptor is 2, the standard error.
 checks a region using \f5Vmdebug\fP or \f5Vmbest\fP for integrity.
 If \f5Vmdebug\fP, this also checks for block overwriting errors.
 On errors, \fIvmdbwarn\fP is called.
-If flag \f5VM_DBCHECK\fP is on, 
+If flag \f5VM_DBCHECK\fP is on,
 \fIvmdbcheck\fP is called at each invocation of
 \fIvmalloc\fP, \fIvmfree\fP, or \fIvmresize\fP.
 .PP