RFR: 7903866: apidiff: add an example to the doc [v2]

[Andrew Haley]

> It's an example, for example. We need more.

Andrew Haley has updated the pull request incrementally with one additional commit since the last revision:

  Add an example

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

Changes:
  - all: https://git.openjdk.org/apidiff/pull/26/files
  - new: https://git.openjdk.org/apidiff/pull/26/files/1cffc32a..74f197f9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=apidiff&pr=26&range=01
 - incr: https://webrevs.openjdk.org/?repo=apidiff&pr=26&range=00-01

  Stats: 5 lines in 1 file changed: 2 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/apidiff/pull/26.diff
  Fetch: git fetch https://git.openjdk.org/apidiff.git pull/26/head:pull/26

PR: https://git.openjdk.org/apidiff/pull/26