Integrated: CODETOOLS-7903051: Fix minor typo in FAQ

[Jonathan Gibbons]

`--enable-option` should be `--enable-preview`

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Commit messages:
 - CODETOOLS-7903051: Fix minor typo in FAQ

Changes: https://git.openjdk.java.net/jtreg/pull/38/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jtreg&pr=38&range=00
  Issue: https://bugs.openjdk.java.net/browse/CODETOOLS-7903051
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jtreg/pull/38.diff
  Fetch: git fetch https://git.openjdk.java.net/jtreg pull/38/head:pull/38

PR: https://git.openjdk.java.net/jtreg/pull/38