RFR: JDK-8303123: Add line break opportunity to single type parameters

[Hannes Wallnöfer]

Please review a simple change to add a `<wbr>` (line break opportunity) tag before type parameters in some type links. This is only used in the first column of member summary tables as this is the only place where we have type names with full type parameters and no natural line break opportunities in a very limited horizontal space. Attached below is a screenshot of the method summary table of `java.net.http.HttpResponse.BodySubscribers` with this fix applied (see JBS issue for a screenshot of the previous rendering).

<img width="1175" alt="return-type-line-breaks" src="https://user-images.githubusercontent.com/15975/226632264-73700740-dc25-429f-acce-d26e24be26cd.png">

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Commit messages:
 - JDK-8303123: Add line break opportunity to single type parameters

Changes: https://git.openjdk.org/jdk/pull/13119/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13119&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8303123
  Stats: 53 lines in 6 files changed: 25 ins; 0 del; 28 mod
  Patch: https://git.openjdk.org/jdk/pull/13119.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13119/head:pull/13119

PR: https://git.openjdk.org/jdk/pull/13119