Fix typo <noupdate>

src/year2/natural-language-processing/sections/_rnn.tex

@@ -81,7 +81,7 @@
                         \[ \vec{f}^{(t)} = \sigma\left( \matr{W}_f \vec{h}^{(t-1)} + \matr{U}_f \vec{x}^{(t)} + \vec{b}_f \right) \]
 
                     \item[Input gate] \marginnote{Input gate}
-                        Controls what part of the input to writer in the cell state:
+                        Controls what part of the input to write in the cell state:
                         \[ \vec{i}^{(t)} = \sigma\left( \matr{W}_i \vec{h}^{(t-1)} + \matr{U}_i \vec{x}^{(t)} + \vec{b}_i \right) \]
 
                     \item[Output gate] \marginnote{Output gate}