[chore][receiver/sqlserver] Update documentation for lock wait rate m…

…etric (#33023)

**Description:** <Describe what has changed.>
<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
As a result of
#32932
the metric `sqlserver.lock.wait.rate` is now available on Windows, or
when directly connecting to a SQL server instance. Since this metric is
always available, it no longer needs extended documentation about
availability.

receiver/sqlserverreceiver/documentation.md

@@ -46,8 +46,6 @@ This metric is only available when running on Windows.
 
 Number of lock requests resulting in a wait.
 
-This metric is only available when running on Windows.
-
 | Unit | Metric Type | Value Type |
 | ---- | ----------- | ---------- |
 | {requests}/s | Gauge | Double |

receiver/sqlserverreceiver/metadata.yaml

@@ -61,7 +61,6 @@ metrics:
     unit: "{requests}/s"
     gauge:
       value_type: double
-    extended_documentation: This metric is only available when running on Windows.
   sqlserver.batch.request.rate:
     enabled: true
     description: Number of batch requests received by SQL Server.