RFR: JDK-8259806: Clean up terminology on the "All Classes" page

[Hannes Wallnöfer]

This is a simple change to replace the "All Classes" with "All Classes and Interfaces" in the heading of and references to the page of the same name.

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Commit messages:
 - JDK-8259806: Clean up terminology on the "All Classes" page

Changes: https://git.openjdk.java.net/jdk/pull/4270/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4270&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8259806
  Stats: 29 lines in 10 files changed: 5 ins; 3 del; 21 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4270.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4270/head:pull/4270

PR: https://git.openjdk.java.net/jdk/pull/4270