[bitset.cons] Fix typo and surrounding inconsistencies.

Fixes #294.

Author: zygoloid

source/utilities.tex

@@ -2291,11 +2291,11 @@
 \tcode{M} is the smaller of \tcode{N} and \tcode{rlen}.
 
 \pnum
-An element of the constructed string has value zero if the
+An element of the constructed object has value zero if the
 corresponding character in \tcode{str}, beginning at position
 \tcode{pos}, is
-\tcode{0} \tcode{zero}.
-Otherwise, the element has the value 1.
+\tcode{zero}.
+Otherwise, the element has the value one.
 Character position \tcode{pos + M - 1} corresponds to bit position zero.
 Subsequent decreasing character positions correspond to increasing bit positions.