listnewconfig: Add option for showing help texts
listnewconfig: Add option for showing help texts

Show the help text for each new symbol if --show-help/-l is passed (-h
might be confused for --help).

Copycat of commit 5d8b42aa7ccb ("kconfig: Add option to get the full
help text with listnewconfig") to the C tools, but with a slightly more
compact output format (indented help text instead of separators).

ulfalizer/Kconfiglib,ulfalizer/Kconfiglib