RFR: 8371009: HttpClient javadoc synchronous example missing HttpRequest variable declaration [v3]

[EunHyunsu]

> Fixes JDK-8371009.
> 
> The synchronous HttpClient example references `request` without defining it.
> This patch adds a minimal HttpRequest initialization immediately before the
> synchronous example (mirroring the asynchronous snippet) so the example
> compiles and runs as-is.

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

  JDK-8371009: fix indent

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/28084/files
  - new: https://git.openjdk.org/jdk/pull/28084/files/0c799d0e..34f8d04b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=28084&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=28084&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/28084.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28084/head:pull/28084

PR: https://git.openjdk.org/jdk/pull/28084