Minor typo in analytic expression for Bayesian evidence in intro_to_g…

…ps.py

Signed-off-by: neel-maniar <[email protected]>

docs/examples/intro_to_gps.py

@@ -474,7 +474,7 @@
 # be analytically expressed as
 # $$
 # \begin{align}
-#         & = 0.5\left(-\underbrace{\mathbf{y}^{\top}\left(\mathbf{K}_{ff} - \sigma_n^2\mathbf{I}_n \right)^{-1}\mathbf{y}}_{\text{Data fit}} -\underbrace{\log\lvert \mathbf{K}_{ff} + \sigma^2_n\rvert}_{\text{Complexity}} -\underbrace{n\log 2\pi}_{\text{Constant}} \right)\,.
+#         & = 0.5\left(-\underbrace{\mathbf{y}^{\top}\left(\mathbf{K}_{ff} + \sigma_n^2\mathbf{I}_n \right)^{-1}\mathbf{y}}_{\text{Data fit}} -\underbrace{\log\lvert \mathbf{K}_{ff} + \sigma^2_n\rvert}_{\text{Complexity}} -\underbrace{n\log 2\pi}_{\text{Constant}} \right)\,.
 # \end{align}
 # $$
 #