semanticate: "i" in section/article ids is semanticated as roman numeral

[weijia-cheng]

In American Indian Stories, there is a story called "Why I Am a Pagan" which translates to the article id why-i-am-a-pagan with our standard article id/file name scheme.

However, se semanticate indiscriminately treats the i as a roman numeral, even when it is inside the id attribute of an article:

diff --git a/src/epub/text/why-i-am-a-pagan.xhtml b/src/epub/text/why-i-am-a-pagan.xhtml
index 977e815..2bd7227 100644
--- a/src/epub/text/why-i-am-a-pagan.xhtml
+++ b/src/epub/text/why-i-am-a-pagan.xhtml
@@ -6,7 +6,7 @@
-               <article id="why-i-am-a-pagan" epub:type="se:short-story">
+               <article id="why-<span epub:type="z3998:roman">i</span>-am-a-pagan" epub:type="se:short-story">