RFR: 8295025: (bf) ByteBuffer "Access to binary data" section suggests putFloat is void

[Brian Burkhalter]

In the "Access to binary data" section of the class specification of `java.nio.ByteBuffer`, change `void putFloat` to `ByteBuffer putFloat`.

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Commit messages:
 - 8295025: (bf) ByteBuffer "Access to binary data" section suggests putFloat is void

Changes: https://git.openjdk.org/jdk/pull/10638/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10638&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8295025
  Stats: 5 lines in 1 file changed: 1 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/10638.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10638/head:pull/10638

PR: https://git.openjdk.org/jdk/pull/10638