[8.8] [DOCS] Adds log pattern analysis in Discover docs (#158059) (#158169)

# Backport

This will backport the following commits from `main` to `8.8`:
- [[DOCS] Adds log pattern analysis in Discover docs
(#158059)](https://github.com/elastic/kibana/pull/158059)

<!--- Backport version: 8.9.7 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sqren/backport)

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Co-authored-by: István Zoltán Szabó <szabosteve@gmail.com>

docs/discover/log-pattern-analysis.asciidoc

@@ -0,0 +1,38 @@
+[[run-pattern-analysis-discover]]
+== Run a pattern analysis on your log data
+
+preview::[]
+
+include::../user/ml/index.asciidoc[tag=log-pattern-analysis-intro]
+Log pattern analysis works on every text field.
+
+This example uses the <<gs-get-data-into-kibana, sample web logs data>>, or you 
+can use your own data.
+
+. Open the main menu, and click *Discover*.
+
+. Expand the {data-source} dropdown, and select *Kibana Sample Data Logs*.
+
+. If you don't see any results, expand the time range, for example, to 
+*Last 15 days*.
+
+. Click the `message` field in the **Available fields** list sidebar and click 
+**Run pattern analysis**.
++
+--
+[role="screenshot"]
+image::images/log-pattern-analysis-available-fields.png["Available fields view in Discover showing the message field selected."]
+
+The pattern analysis starts. The results are displayed in a flyout when the 
+analysis is complete.
+
+[role="screenshot"]
+image::images/log-pattern-analysis-results.png["Log pattern analysis results in Discover."]
+--
+
+. (optional) Apply filters to one or more patterns. *Discover* only displays 
+documents that match the selected patterns. Additionally, you can remove 
+selected patterns from *Discover*, resulting in the display of only those 
+documents that don't match the selected pattern. These options enable you to 
+remove unimportant messages and focus on the more important, actionable data 
+during troubleshooting.

docs/user/discover.asciidoc

@@ -344,4 +344,6 @@ include::{kib-repo-dir}/discover/save-search.asciidoc[]
 
 include::{kib-repo-dir}/discover/field-statistics.asciidoc[]
 
-include::{kib-repo-dir}/discover/search-sessions.asciidoc[]
+include::{kib-repo-dir}/discover/log-pattern-analysis.asciidoc[]
+
+include::{kib-repo-dir}/discover/search-sessions.asciidoc[]

docs/user/ml/index.asciidoc

@@ -151,11 +151,14 @@ image::user/ml/images/ml-explain-log-rate.png[Log rate spike explained]
 
 preview::[]
 
+// The following intro is used on the `run-pattern-analysis-discover` page.
+//tag::log-pattern-analysis-intro[]
 Log pattern analysis helps you to find patterns in unstructured log messages and 
 makes it easier to examine your data. It performs categorization analysis on a 
 selected field of a {data-source}, creates categories based on the data and 
 displays them together with a chart that shows the distribution of each category 
 and an example document that matches the category.
+//end::log-pattern-analysis-intro[]
 
 You can find log pattern analysis under **{ml-app}** > **AIOps Labs** where you 
 can select the {data-source} or saved search that you want to analyze, or in