[DOCS] Fix substitution variables (#18224)

Author: lcawl

docs/release-notes/index.md

@@ -31,7 +31,7 @@ To check for security updates, go to [Security announcements for the Elastic sta
 
 ### Fixes [logstash-9.1.4-fixes]
 
-* Gauge type metrics, such as current and peak connection counts of Elastic Agent, are now available in the `_node/stats` API response when the `vertices=true` parameter is included. These metrics are particularly useful for monitoring {ls} plugin activity on the {ls} Integration dashboards [#18090](https://github.com/elastic/logstash/pull/18090)
+* Gauge type metrics, such as current and peak connection counts of Elastic Agent, are now available in the `_node/stats` API response when the `vertices=true` parameter is included. These metrics are particularly useful for monitoring {{ls}} plugin activity on the {{ls}} Integration dashboards [#18090](https://github.com/elastic/logstash/pull/18090)
 * Improve logstash release artifacts file metadata: mtime is preserved when buiilding tar archives [#18091](https://github.com/elastic/logstash/pull/18091)
 
 
@@ -182,8 +182,8 @@ The Elasticsearch Input now provides [support](https://github.com/logstash-plugi
 
 ### Fixes [logstash-9.0.7-fixes]
 
-* Gauge type metrics, such as current and peak connection counts of Elastic Agent, are now available in the `_node/stats` API response when the `vertices=true` parameter is included. These metrics are particularly useful for monitoring {ls} plugin activity on the {ls} Integration dashboards. [#18089](https://github.com/elastic/logstash/pull/18089)
-* Improve logstash release artifacts file metadata: mtime is preserved when buiilding tar archives. [#18111](https://github.com/elastic/logstash/pull/18111)
+* Gauge type metrics, such as current and peak connection counts of Elastic Agent, are now available in the `_node/stats` API response when the `vertices=true` parameter is included. These metrics are particularly useful for monitoring {{ls}} plugin activity on the {{ls}} Integration dashboards. [#18089](https://github.com/elastic/logstash/pull/18089)
+* Improve logstash release artifacts file metadata: mtime is preserved when building tar archives. [#18111](https://github.com/elastic/logstash/pull/18111)
 
 ### Plugins [logstash-plugin-9.0.7-changes]
 
@@ -387,4 +387,4 @@ Check out the [security advisory](https://discuss.elastic.co/c/announcements/sec
 
 **Tcp Output - 7.0.0**
 
-* Remove deprecated SSL settings [#58](https://github.com/logstash-plugins/logstash-output-tcp/pull/58)
+* Remove deprecated SSL settings [#58](https://github.com/logstash-plugins/logstash-output-tcp/pull/58)