I think it should be being instead of begin.

--- pages/lang_altertable.in.orig       Thu Aug 27 20:08:11 2020
+++ pages/lang_altertable.in    Thu Aug 27 19:14:04 2020
@@ -49,7 +49,7 @@
 <p> Prior to version 3.26.0 ([dateof:3.26.0]), FOREIGN KEY references
 to a table that is renamed were only edited if the
 [PRAGMA foreign_keys=ON], or in other words if
-[foreign key constraints] were begin enforced.  With
+[foreign key constraints] were being enforced.  With
 [PRAGMA foreign_keys=OFF], FOREIGN KEY constraints would not be changed
 when the table that the foreign key referred to (the "[parent table]")
 was renamed.  Beginning with version 3.26.0, FOREIGN KEY constraints