Replace a couple of ascii emdashes

Author: AWhetter

doc/source/decisions/003-path-sequence-inherits-from-set.rst

@@ -64,8 +64,8 @@ With sorting would require the arithmetic sequences given to a file number set
 to be sorted, before being split such that they don't overlap.
 Given the use cases, most of the time the sorting will take :math:`n` time
 if we're using a :math:`\Omega(n)` time sort algorithm.
-Detecting whether two sequences overlap is simple --
-though does require in depth mathemtical concepts -- for integers,
+Detecting whether two sequences overlap is simple —
+though does require in depth mathemtical concepts — for integers,
 but is more involved for decimals (see Appendix A).
 If maintaining this complex code ever becomes a problem,
 we would always resort to looping over every item in the sequences.