RFR: Update committer description

[Jesper Wilhelmsson]

Clarified that the number of commits in the project isn't everything that counts.

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

Commit messages:
 - Update committer description

Changes: https://git.openjdk.java.net/guide/pull/88/files
 Webrev: https://webrevs.openjdk.java.net/?repo=guide&pr=88&range=00
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/guide/pull/88.diff
  Fetch: git fetch https://git.openjdk.java.net/guide pull/88/head:pull/88

PR: https://git.openjdk.java.net/guide/pull/88