RFR: Cleaned up tidy warnings

[Jesper Wilhelmsson]

Cleaned up two more html tidy warnings.

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Commit messages:
 - Added table summary

Changes: https://git.openjdk.java.net/guide/pull/53/files
 Webrev: https://webrevs.openjdk.java.net/?repo=guide&pr=53&range=00
  Stats: 2 lines in 2 files changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/guide/pull/53.diff
  Fetch: git fetch https://git.openjdk.java.net/guide pull/53/head:pull/53

PR: https://git.openjdk.java.net/guide/pull/53