Move the dummy article to input/

`plugins/input/dummy.md` was the last file left under `plugins/`. Every
other article moved out of that directory long ago, but this one stayed
behind and was never added to SUMMARY.md, so GitBook does not publish it
and `v1.0/articles/in_dummy` returns 404.

`in_dummy` was renamed `in_sample` in v1.11.12, but the plugin itself is
still shipped, so readers who land on the old URL should still get the
article that explains the rename instead of a 404.

* Move it to `input/dummy.md`, next to the other input plugin articles,
  and add it to SUMMARY.md right after `sample`.
* Point the `v1.0/articles/in_dummy` redirect at the new path.
* Fix its link to the `sample` article. `/input/sample.md` is a
  root-absolute path and does not resolve.
* Match the conventions of the surrounding articles: `# dummy` as the
  title, like `input/sample.md` and the rest, and the current one-line
  footer. This was the only file in the repository still carrying the
  old hard-wrapped footer with a horizontal rule.

It is intentionally left out of the plugin list in `input/README.md`,
since `dummy` is a deprecated alias rather than a plugin to choose;
`monitor_agent` is listed in SUMMARY.md but not there either.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Signed-off-by: Shizuo Fujita <fujita@clear-code.com>

Author: Watson1978

.gitbook.yaml

@@ -84,7 +84,7 @@ redirects:
   v1.0/articles/in_exec: plugins/input/exec.md
   v1.0/articles/in_syslog: plugins/input/syslog.md
   v1.0/articles/in_unix: plugins/input/unix.md
-  v1.0/articles/in_dummy: plugins/input/dummy.md
+  v1.0/articles/in_dummy: input/dummy.md
 
   # Plugin/Output
   v1.0/articles/output-plugin-overview: plugins/output/README.md

SUMMARY.md

@@ -85,6 +85,7 @@
   * [syslog](input/syslog.md)
   * [exec](input/exec.md)
   * [sample](input/sample.md)
+  * [dummy](input/dummy.md)
   * [monitor\_agent](input/monitor_agent.md)
   * [windows\_eventlog](input/windows_eventlog.md)
 * [Output Plugins](output/README.md)

input/dummy.md

@@ -0,0 +1,16 @@
+# dummy
+
+`in_dummy` has been renamed `in_sample` since Fluentd v1.11.12. See [`sample` input plugin](sample.md) article for more details.
+
+You can keep using the following configuration in v1:
+
+```text
+<source>
+  @type dummy
+  dummy {"hello":"world"}
+</source>
+```
+
+Fluentd v2 will remove this plugin name.
+
+If this article is incorrect or outdated, or omits critical information, please [let us know](https://github.com/fluent/fluentd-docs-gitbook/issues?state=open). [Fluentd](http://www.fluentd.org/) is an open-source project under [Cloud Native Computing Foundation \(CNCF\)](https://cncf.io/). All components are available under the Apache 2 License.