Missing a negative sign on the exponent for RoPE #313

• File: labml_nn/transformers/rope/__init__.py
• Line: 95
• Quote: The paper suggests using $\Theta = {\theta_i = 10000^{\frac{2(i-1)}{d}}, i \in [1, 2, ..., \frac{d}{2}]}$ for the $\frac{d}{2}$ pairs of features.

I thing it should be: $\Theta = {\theta_i = 10000^{-\frac{2(i-1)}{d}}, i \in [1, 2, ..., \frac{d}{2}]}$