[sequence.reqmts] and [forwardlist.modifiers]: Fix occurrences of "i1" that are supposed to be "il". Thanks to Jeffrey Yasskin!

Author: Stefanus Du Toit

source/containers.tex

@@ -907,8 +907,8 @@
 element inserted into \tcode{a}, or \tcode{p} if \tcode{i == j}.
 
 \pnum
-The iterator returned from \tcode{a.insert(p, i1)} points to the copy of the first
-element inserted into \tcode{a}, or \tcode{p} if \tcode{i1} is empty.
+The iterator returned from \tcode{a.insert(p, il)} points to the copy of the first
+element inserted into \tcode{a}, or \tcode{p} if \tcode{il} is empty.
 
 \pnum
 The iterator returned from \tcode{a.emplace(p, args)} points to the new element
@@ -3533,7 +3533,7 @@
 
 \pnum
 \returns
-An iterator pointing to the last inserted element or \tcode{position} if \tcode{i1} is empty.
+An iterator pointing to the last inserted element or \tcode{position} if \tcode{il} is empty.
 \end{itemdescr}