docs(database): name the column types the debugging snippets assume

Both functions read specific types into declared variables. Naming only the
column names left a reader guessing. Verified both run against tables built
to the documented shape.

apps/docs/content/guides/database/debugging-functions.mdx

@@ -75,7 +75,7 @@ assert <some condition>, 'message';
 For example:
 
 ```sql
--- assumes an attendance_table with student and id columns
+-- assumes an attendance_table with an id uuid column and a student text column
 create function assert_example(name text)
 returns uuid
 language plpgsql
@@ -127,7 +127,7 @@ For a more complex function, or for harder debugging, log the following:
 - Start and end of function calls
 
 ```sql
--- assumes a some_table with col_1 and col_2 columns
+-- assumes a some_table with a col_1 int column and a col_2 text column
 create or replace function advanced_example(num int default 10)
 returns text
 language plpgsql