RFR: 8299836: Make `user.timezone` system property searchable [v2]

[Justin Lu]

> The system property _user.timezone_ is specified in the _TimeZone.getDefault()_ and _TimeZone.setDefault()_  methods. The javadoc search box should be able to match on the system property name.
> 
> This change replaces the **@code** tag with the **@systemProperty** tag for instances of _user.timezone_ when appropriate.

Justin Lu has updated the pull request incrementally with one additional commit since the last revision:

  Toggle first instance as a system property, revert rest

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Changes:
  - all: https://git.openjdk.org/jdk/pull/11915/files
  - new: https://git.openjdk.org/jdk/pull/11915/files/8962d0d4..6935162e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11915&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11915&range=00-01

  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/11915.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11915/head:pull/11915

PR: https://git.openjdk.org/jdk/pull/11915