RFR: 8371009: HttpClient javadoc synchronous example missing HttpRequest variable declaration [v2]

[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:

  Apply review suggestion: create client before request in HttpClient example

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/28084/files
  - new: https://git.openjdk.org/jdk/pull/28084/files/34421a70..0c799d0e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=28084&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=28084&range=00-01

  Stats: 8 lines in 1 file changed: 4 ins; 4 del; 0 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