rework setIntersection
std.stdio: Fix DDoc syntax in thrown exception documentation

Introduced in 402af9d0c400cb1f47d4b2b6e16bfac6b875fbd6
Merge pull request #1821 from CyberShadow/ddoc-syntax-fixes-7

std.stdio: Fix DDoc syntax in thrown exception documentation
Merge pull request #1801 from monarchdodra/setIntersection

rework setIntersection