{Doc} Track 2 Migration Guidance (#16484)

* {Doc} Track 2 Migration Guidance

* Update doc/track_2_migration_guidance.md

Co-authored-by: Jiashuo Li <jiasli@microsoft.com>

* Update doc/track_2_migration_guidance.md

Co-authored-by: Jiashuo Li <jiasli@microsoft.com>

doc/track_2_migration_guidance.md

@@ -24,7 +24,7 @@ Below is a list of typical issues.
 
 ### Long running operation function name change
 
-Long running operations have changed their function names in Track 2 SDK. A `begin_` prefix is added. E.g. `create_or_update` becomes `begin_create_or_update`. `delete` becomes `begin_delete`. It is a naming convention in Track 2 SDK to indicate that an operation is a long running operation.
+Long running operations have changed their function names in Track 2 SDK. A `begin_` prefix is added. For example, `create_or_update` becomes `begin_create_or_update`. `delete` becomes `begin_delete`. It is a naming convention in Track 2 SDK to indicate that an operation is a long running operation. Test cases can reveal most instances, but if a command has no test, it may be missed. A reliable approach is going through all methods to see whether they are long running operations.
 
 ### Property name change