Corollary 1
Tag 006X, permanent. Cite it as [Bourbaki, Tag 006X].
Algebra, VIII, p. 99, § 6. Morita Equivalence of Modules and Algebras
The countermodule of a generating module is projective and finitely generated. The countermodule of a finitely generated projective module is generating.
Let A be a -algebra, and let M be an A-module. We denote the opposite -algebra of the algebra End by B. The corollary follows from Proposition 4 applied to the -bimodule M.
Bourbaki sets the proof directly after the statement, and the corpus does not separate them, so what is above is the statement and its proof together.