DOCUMENTATION: Fix missing/wrong TSDoc of APIs having optional host parameter (#2371)

markdown/bitburner.ns.gethacktime.md

@@ -9,7 +9,7 @@ Get the execution time of a hack() call.
 **Signature:**
 
 ```typescript
-getHackTime(host: string): number;
+getHackTime(host?: string): number;
 ```
 
 ## Parameters
@@ -42,7 +42,7 @@ string
 
 </td><td>
 
-Hostname/IP of target server.
+_(Optional)_ Hostname/IP of target server. Optional. Defaults to the server the calling script is running on.
 
 
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