This was generated as follows:
 - cythonize sagemath and save all "Implicit noexcept" warnings
 - sort -u and parse to produce a list of unique filename + line number
 - pipe the list to the following snippet:

    while read file line; do
        sed "$file" -ne "$line"p | grep -q -e noexcept -e '<.*>' ||
        sed -i "$file" -e "$line"'s/\(\( \+\(with \|no\)gil *\)\?[:,]\?\( *#.*\)\?\)$/ noexcept\1/'
    done

 - fix one incorrectly placed `noexcept`
 - fix a doctest due to code change

The previous run only fixed files in the sagemath-standard distribution,
just because we started with a list of warnings produced when compiling
just sagemath-standard.

This time we apply the same strategy to files in the other
distributions.

This reverts commit 131b747.