Added information regarding the maximum length of a Workflow ID and its match pattern (#18355)

Author: bruxodasilva

src/content/docs/workflows/build/workers-api.mdx

@@ -173,7 +173,7 @@ Create (trigger) a new instance of the given Workflow.
 
   * `options` - optional properties to pass when creating an instance.
 
-An ID is automatically generated, but a user-provided ID can be specified. This can be useful when mapping Workflows to users, merchants or other identifiers in your system.
+An ID is automatically generated, but a user-provided ID can be specified (up to 64 characters [^1]). This can be useful when mapping Workflows to users, merchants or other identifiers in your system.
 
 ```ts
 // Create a new Workflow instance with your own ID:
@@ -293,3 +293,5 @@ type InstanceStatus = {
   output?: object;
 };
 ```
+
+[^1]: Match pattern: _```^[a-zA-Z0-9_][a-zA-Z0-9-_]*$```_

src/content/docs/workflows/reference/limits.mdx

@@ -23,14 +23,16 @@ Many limits are inherited from those applied to Workers scripts and as documente
 | Maximum `step.sleep` duration             | 365 days (1 year) [^1] |
 | Maximum steps per Workflow                | 256 [^1] |
 | Maximum Workflow executions               | 100,000 per day [shared with Workers daily limit](/workers/platform/limits/#worker-limits) | Unlimited |
-| Concurrent Workflow instances (executions) | 25 | 100 [^1] |
+| Concurrent Workflow instances (executions)   | 25 | 100 [^1] |
 | Retention limit for completed Workflow state | 3 days | 30 days [^2] |
-| Maximum length of a Workflow ID | 64 bytes |
+| Maximum length of a Workflow ID [^4]         | 64 characters |
 
 [^1]: This limit will be reviewed and revised during the open beta for Workflows. Follow the [Workflows changelog](/workflows/reference/changelog/) for updates.
 
 [^2]: Workflow state and logs will be retained for 3 days on the Workers Free plan and for 7 days on the Workers Paid plan.
 
 [^3]: A Workflow instance can run forever, as long as each step does not take more than the CPU time limit and the maximum number of steps per Workflow is not reached.
 
+[^4]: Match pattern: _```^[a-zA-Z0-9_][a-zA-Z0-9-_]*$```_
+
 <Render file="limits_increase" product="workers" />