perlhack.pod tidied

In accordance with the comment at the top of the file, before I make other
changes to it.

Remove trailing whitespace.

For: RT #119599
Consistent indent on shell commands

Most verbatim lines with shell commands had 2 spaces before the % prompt.
A few had 1 or 4 spaces. Make them all 2.

Remove trailing whitespace.

For: RT #119599
Have perlbug report version being patched

In the Super Quick Patch Guide, run the perlbug and perl from the working
copy that the patch is against, so the bug report contains relevant
version and configuration data, rather than that of whichever system perl
the reporter happens to have installed.

For: RT #119599