docs: fix description

All the current DB drivers throw an exception when a query error occurs.
See #6912

MySQLi driver sets `mysqli_report(MYSQLI_REPORT_ALL & ~MYSQLI_REPORT_INDEX)`
that throws mysqli_sql_exception.

SQLite3, Postgres and OCI8 drivers throw ErrorException because of Error Handler.

SQLSRV driver has different implementaion. It throws DatabaseException when the
query return value is false.

Author: kenjis

user_guide_src/source/database/transactions.rst

@@ -48,9 +48,8 @@ or failure of any given query.
 .. note:: Since v4.3.0, ``DBDebug`` is true by default in all environments.
     When ``DBDebug`` is true, if a query error occurs, all the queries
     will be rolled backed, and an exception will be thrown.
-    In previous versions, ``DBDebug`` was false in production environment,
-    and different database drivers might throw different exception classes
-    or did not throw exceptions.
+    In previous versions, ``DBDebug`` was false only in production environment,
+    and different database drivers might throw different exception classes.
 
 Strict Mode
 ===========
@@ -68,9 +67,8 @@ Strict Mode can be disabled as follows:
 .. note:: Since v4.3.0, ``DBDebug`` is true by default in all environments.
     When ``DBDebug`` is true, if a query error occurs, all the queries
     will be rolled backed, and an exception will be thrown.
-    In previous versions, ``DBDebug`` was false in production environment,
-    and different database drivers might throw different exception classes
-    or did not throw exceptions.
+    In previous versions, ``DBDebug`` was false only in production environment,
+    and different database drivers might throw different exception classes.
 
 .. _transactions-managing-errors:
 
@@ -88,9 +86,8 @@ If the ``DBDebug`` is false, you can manage your own errors like this:
 .. note:: Since v4.3.0, ``DBDebug`` is true by default in all environments.
     When ``DBDebug`` is true, if a query error occurs, all the queries
     will be rolled backed, and an exception will be thrown.
-    In previous versions, ``DBDebug`` was false in production environment,
-    and different database drivers might throw different exception classes
-    or did not throw exceptions.
+    In previous versions, ``DBDebug`` was false only in production environment,
+    and different database drivers might throw different exception classes.
 
 Disabling Transactions
 ======================