Streamline description of versionsort (incorporate suggestion from Ralf)

Author: joshtriplett

src/doc/style-guide/src/README.md

@@ -112,10 +112,9 @@ For the purposes of the Rust style, to compare two strings for version-sorting:
 - Compare the strings by (Unicode) character as normal, finding the index of
   the first differing character. (If the two strings do not have the same
   length, this may be the end of the shorter string.)
-- For both strings, determine the longest sequence of ASCII digits containing
-  either that character or the character before. (If either string doesn't have
-  such a sequence of ASCII digits, fall back to comparing the strings as
-  normal.)
+- For both strings, determine the longest sequence of ASCII digits that either
+  contains or ends at that index. (If either string doesn't have such a
+  sequence of ASCII digits, fall back to comparing the strings as normal.)
 - Compare the numeric values of the number specified by the sequence of digits.
   (Note that an implementation of this algorithm can easily check this without
   accumulating copies of the digits or converting to a number: after skipping