RFR: 8362244: Devkit's Oracle Linux base OS keyword is incorrectly documented [v2]

[Volkan Yazici]

> `open/doc/building.md` uses the incorrect `OEL6` keyword to denote the Oracle Enterprise Linux base OS distribution for Devkit – replaced it with the correct one instead, i.e., `OL`.

Volkan Yazici has updated the pull request incrementally with one additional commit since the last revision:

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Changes:
  - all: https://git.openjdk.org/jdk/pull/26311/files
  - new: https://git.openjdk.org/jdk/pull/26311/files/d267739d..0d85899a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26311&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26311&range=00-01

  Stats: 6 lines in 1 file changed: 0 ins; 2 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/26311.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26311/head:pull/26311

PR: https://git.openjdk.org/jdk/pull/26311