RFR: 8267683: rfc7301Grease8F value not displayed correctly in SSLParameters javadoc

[Bradford Wetmore]

Simple typo fix.  Somehow the trailing "u" got omitted, so the code won't parse when fed into the compiler.

Resulting javadoc output now compiles.

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Commit messages:
 - Codereview Comments.
 - 8267683: rfc7301Grease8F value not displayed correctly in SSLParameters javadoc

Changes: https://git.openjdk.java.net/jdk/pull/4193/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4193&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8267683
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4193.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4193/head:pull/4193

PR: https://git.openjdk.java.net/jdk/pull/4193