fix: Update client span duration text labels

In the image the three scenarios are labeled A/B/C but in the text they are 1/2/3. This is confusing.

src/content/docs/distributed-tracing/ui-data/understand-use-distributed-tracing-ui.mdx

@@ -643,9 +643,9 @@ Here are some additional distributed tracing UI details, rules, and limits:
         src={newRelicDistributedTracingClientSpanTime}
       />
 
-    1. When a client span is longer than the server span, this could be due to latency in a number of areas, such as: network time, queue time, DNS resolution time, or from a load balancer that we cannot see.
-    2. When a client span starts and ends before a server span begins, this could be due to clock skew, or due to the server doing asynchronous work that continues after sending the response.
-    3. When a client span starts after a server span, this is most likely clock skew.
+    A. When a client span is longer than the server span, this could be due to latency in a number of areas, such as: network time, queue time, DNS resolution time, or from a load balancer that we cannot see.
+    B. When a client span starts and ends before a server span begins, this could be due to clock skew, or due to the server doing asynchronous work that continues after sending the response.
+    C. When a client span starts after a server span, this is most likely clock skew.
   </Collapser>
 
   <Collapser