patch 9.0.1998: xxd: cannot reverse a bit dump

Problem:  xxd: cannot reverse a bit dump
Solution: implement reversing the bit dump using -b -r

closes: #13286

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: tristhaus <tristhaus@yahoo.de>
diff --git a/runtime/doc/xxd.1 b/runtime/doc/xxd.1
index 7cd6ae8..f5a7c65 100644
--- a/runtime/doc/xxd.1
+++ b/runtime/doc/xxd.1
@@ -64,7 +64,7 @@
 This option writes octets as eight digits "1"s and "0"s instead of a normal
 hexadecimal dump. Each line is preceded by a line number in hexadecimal and
 followed by an ASCII (or EBCDIC) representation. The command line switches
-\-r, \-p, \-i do not work with this mode.
+\-p, \-i do not work with this mode.
 .TP
 .IR "\-c cols " | " \-cols cols"
 Format
@@ -133,7 +133,9 @@
 .I \-r \-p
 to read plain hexadecimal dumps without line number information and without a
 particular column layout. Additional whitespace and line breaks are allowed
-anywhere.
+anywhere. Use the combination
+.I \-r \-b
+to read a bits dump instead of a hex dump.
 .TP
 .IR \-R " " when
 In output the hex-value and the value are both colored with the same color