RFR: 8265444: Javadocs: jdk.jshell - small typo

[Jan Lahoda]

Fixing typo in jdk.jshell's javadoc.

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Commit messages:
 - 8265444: Javadocs: jdk.jshell - small typo

Changes: https://git.openjdk.java.net/jdk/pull/4336/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4336&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8265444
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4336.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4336/head:pull/4336

PR: https://git.openjdk.java.net/jdk/pull/4336