Harmonize `cat -n` format in tools

[ericproulx]

cat -n format is the following: 6 spaces + lines number + tab + content

In ruby: "#{line_no.to_s.rjust(6)}\t#{text}"

None of the following tools are actually using the format (even if its claiming it in the comments)

• LoadSkill = 6 spaces + → + line_number + content
• MemoryRead = 6 spaces + space + line_number + content
• Read = 6 spaces + → + line_number + content
• ScratchPadRead = 6 spaces + → + line_number + content