[receiver/mysql] renaming metric

Author: Sprakhar97

.chloggen/mysql-open-resources-slow-launch-threads.yaml

@@ -7,7 +7,7 @@ change_type: enhancement
 component: receiver/mysql
 
 # A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
-note: Add mysql.resources.open and mysql.threads.slow_launch metrics, disabled by default.
+note: Add mysql.resources.open and mysql.thread.slow_launch metrics, disabled by default.
 
 # Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
 issues: [49867]

receiver/mysqlreceiver/documentation.md

@@ -673,7 +673,7 @@ The number of hits, misses or overflows for open tables cache lookups.
 | ---- | ----------- | ------ | ----------------- | ------------------- |
 | status | The status of cache access. | Str: ``hit``, ``miss``, ``overflow`` | Recommended | - |
 
-### mysql.threads.slow_launch
+### mysql.thread.slow_launch
 
 The number of threads that have taken more than slow_launch_time seconds to create.