Typos (wrong variable name) in exercise "Neural Machine Translation"

[joduss]

𝑒⟨𝑡,𝑡′⟩  is then used when computing the attention  𝑎⟨𝑡,𝑡′⟩  that  𝑦⟨𝑡⟩  should pay to  𝑎⟨𝑡′⟩ .

where 𝑎⟨𝑡,𝑡′⟩ should be 𝛼⟨𝑡,𝑡′⟩

[TMosh]

Thanks for your report.