[list.modifiers] Remove stray newline (#7480)

Author: jwakely

source/containers.tex

@@ -8215,7 +8215,6 @@
 \begin{itemdecl}
 iterator erase(const_iterator position);
 iterator erase(const_iterator first, const_iterator last);
-
 void pop_front();
 void pop_back();
 void clear() noexcept;