Fixing misspelling in abstract of ms.

tex/manuscript/abstract.tex

@@ -31,6 +31,6 @@
 Alaskan populations of threespine sticklebacks (\spp{Gasterosteus aculeatus})
 were likely spurious, and driven by a combination of misspecified prior
 assumptions and the lack of information about the timing of demographic changes
-when invariant charcters are ignored.
+when invariant characters are ignored.
 We conclude by discussing potential avenues to improve the estimation of
 synchronous demographic changes across populations.