Update license rule to either deprecate/demote as false positive or mere clue

When detected https://github.com/nexB/scancode-toolkit/blob/b1a3620e89335f302f18c56fd4161655e18889c1/src/licensedcode/data/rules/epl-1.0_and_other-copyleft_2.RULE#L10 this text is NOT a license, but rather a comment about license and an offer to obtain the corresponding source code of copyleft-licensed binaries

We could either:
- demote this to mere clue, OR
- make this a false positive, OR
- deprecate it, OR
- create a new category for these (and likely a few other texts) that are source code offers.