docs: Updated/extended halshow doc

Author: hansu

docs/man/man1/halshow.1

@@ -24,26 +24,35 @@
 .\"
 .TH HALSHOW "1"  "2020-08-26" "LinuxCNC Documentation" "The Enhanced Machine Controller"
 .SH NAME
-halshow \- short description
+halshow \- Show HAL parameters, pins and signals
 .SH SYNOPSIS
-.B halshow
+.B halshow [Options] [watchfile]
 
+.SH OPTIONS
+           --help    (help)
+           --fformat format_string_for_float
+           --iformat format_string_for_int
+
+For format see 
+.UR https://www.tcl.tk/man/tcl8.6.11/TclCmd/format.html
+.UE
+
+Example: 
+"%.5f" displays a float with 5 digits right of the decimal point
 .SH DESCRIPTION
 \fBhalshow\fR creates a GUI interface to view and interact with a running
 HAL session. 
 It is documented in the PDF and HTML docs much more completely than is
 possible in a manpage:
-http://linuxcnc.org/docs/html/hal/halshow.html
-
+.UR http://linuxcnc.org/docs/html/hal/halshow.html
+.UE
 
 .SH "SEE ALSO"
 \fBLinuxCNC(1)\fR
 
 Much more information about LinuxCNC and HAL is available in the LinuxCNC
 and HAL User Manuals, found at /usr/share/doc/LinuxCNC/.
 
-.SH HISTORY
-
 .SH BUGS
 None known at this time. 
 .PP

docs/src/hal/halshow.txt

@@ -42,6 +42,7 @@ and used a file named my.halshow in the current directory:
 ----
 $ halshow  --fformat ".5f" ./my.halshow
 ----
+For more information regarding the format, please refer to https://www.tcl.tk/man/tcl8.6.11/TclCmd/format.html
 
 == HAL Tree Area