bug in help text for sed

[FischerR.External]

Bug: Documentation of "-r" is missing from the Synopsis which is printed
when requesting the "-help" option.

> sed.exe --version
GNU sed version 3.02

The --help does *not* list the "-r" switch (allow extended regular expressions),
though the switch is correctly recognized.

> sed.exe --help
...
  -n, --quiet, --silent
                 suppress automatic printing of pattern space
  -e script, --expression=script
                 add the script to the commands to be executed
  -f script-file, --file=script-file
                 add the contents of script-file to the commands to be executed
      --help     display this help and exit
  --text     switch to text mode
  -V, --version  output version information and exit
...
> echo abc | sed.exe -r "s/a(b)c/x\1/"
xb
> echo abc | sed.exe "s/a(b)c/x\1/"
abc