RFR: 1422: Remove the need to type `JEP-` or `jep-` prefix in `jep` command

[Guoxiong Li]

Hi all,

This patch permits the strange grammer like `/jep jEP-123` and removes the need of the `JEP-` or `jep-` prefix.
When the prefix (`JDK-`, `JEP-` or others) is not provided, the bot treats it as a JEP ID firstly.
If the issue is not found, the bot then treats it as an issue ID.

Thanks for taking the time to review.

Best Regards,
-- Guoxiong

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Commit messages:
 - 1422: Remove the need to type `JEP-` or `jep-` prefix in `jep` command

Changes: https://git.openjdk.java.net/skara/pull/1311/files
 Webrev: https://webrevs.openjdk.java.net/?repo=skara&pr=1311&range=00
  Issue: https://bugs.openjdk.java.net/browse/SKARA-1422
  Stats: 82 lines in 2 files changed: 58 ins; 10 del; 14 mod
  Patch: https://git.openjdk.java.net/skara/pull/1311.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/1311/head:pull/1311

PR: https://git.openjdk.java.net/skara/pull/1311