[tab:headers.cpp] Rebalance table columns (#6556)

Author: AlisdairM

source/lib-intro.tex

@@ -1143,8 +1143,8 @@
 \tcode{<sstream>} \\
 \tcode{<stack>} \\
 \tcode{<stacktrace>} \\
-\tcode{<stdexcept>} \\
 \columnbreak
+\tcode{<stdexcept>} \\
 \tcode{<stdfloat>} \\
 \tcode{<stop_token>} \\
 \tcode{<streambuf>} \\