Fix sphinx reference in pygmt/src/sphdistance.py
Fixes a minor typo in the sphinx :gmt-docs: reference.
@@ -38,7 +38,7 @@ def sphdistance(data=None, x=None, y=None, **kwargs):
then processed to calculate the nearest distance to each
node of the lattice and written to the specified grid.
- Full option list at :gmt-docs:`sphdistance.html
+ Full option list at :gmt-docs:`sphdistance.html`
{aliases}
