RFR: 8253470: Javadoc clean up in Filter and Headers

[Patrick Concannon]

Hi,

Could someone please review my doc-only fix for JDK-8253470 - 'Javadoc clean up in Filter and Headers' ?

This fix is set of formatting changes intended to clean up the javadoc of the following classes :

`com.sun.net.httpserver.Filter`
`com.sun.net.httpserver.Filter.Chain`
`com.sun.net.httpserver.Headers`

This issue is a sub-task of [JDK-8252822](https://bugs.openjdk.java.net/browse/JDK-8252822)

Kind regards,
Patrick

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Commit messages:
 - 8253470: Javadoc clean up in Filter and Headers

Changes: https://git.openjdk.java.net/jdk/pull/429/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=429&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8253470
  Stats: 113 lines in 2 files changed: 40 ins; 16 del; 57 mod
  Patch: https://git.openjdk.java.net/jdk/pull/429.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/429/head:pull/429

PR: https://git.openjdk.java.net/jdk/pull/429