RFR: 8304845: COPYING in MUSCLE library includes incomplete license [v2]

[Valerie Peng]

> Could someone please help review this fix? Besides updating the md and COPYING files to address the incomplete license issue, this PR also updates the version to 1.9.9.

Valerie Peng has updated the pull request incrementally with one additional commit since the last revision:

  typo fix

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/13409/files
  - new: https://git.openjdk.org/jdk/pull/13409/files/aec13c1b..a9151092

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13409&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13409&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/13409.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13409/head:pull/13409

PR: https://git.openjdk.org/jdk/pull/13409