doc: build:kconfig:settings rewise CONF_FILE description

make item#2 as part of item#1 to reduce confusions.

(cherry picked from commit a275e45)

Original-Signed-off-by: Yanfeng Liu <yfliu2008@qq.com>
GitOrigin-RevId: a275e45
Change-Id: If4013db317a04df355fa68ad102a3b6d130ad60d
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/zephyr/+/4933964
Tested-by: ChromeOS Prod (Robot) <chromeos-ci-prod@chromeos-bot.iam.gserviceaccount.com>
Commit-Queue: Keith Short <keithshort@chromium.org>
Tested-by: Keith Short <keithshort@chromium.org>
Reviewed-by: Keith Short <keithshort@chromium.org>

doc/build/kconfig/setting.rst

@@ -149,8 +149,8 @@ used.
 
    3. From the CMake variable cache
 
-#. Otherwise if ``CONF_FILE`` is set, and a single configuration file of the
-   form :file:`prj_<build>.conf` is used, then if file
+   Furthermore if ``CONF_FILE`` is set as single configuration file of the
+   form :file:`prj_<build>.conf` and if file
    :file:`boards/<BOARD>_<build>.conf` exists in same folder as file
    :file:`prj_<build>.conf`, the result of merging :file:`prj_<build>.conf` and
    :file:`boards/<BOARD>_<build>.conf` is used.