fix typos

docs/src/contributing.md

@@ -5,7 +5,7 @@ We welcome any contributions to this package.
 Some recommended areas are:
 
 * Taking the [MPD Equations](MPD.md) beyond second order in the expansion.
-* Extension to general spin supplementary conditions, beyond. 
+* Extension to general spin supplementary conditions, beyond Tulczyjew-Dixon.
 * Generalisation to arbitrary spacetime metrics, not just Kerr.
 * Calculation of gravitational waveforms using e.g. [numerical kludge](https://arxiv.org/abs/gr-qc/0607007) approach (or other).
 * Extension to hyperbolic systems, e.g. [Li et. al. 2021](https://arxiv.org/abs/2110.03494).