std: add a Clone impl for HashSet.
Fixed #8451 - extra::stats::write_boxplot() applied to negative or zero sample values
Fixed option_env! type

The type of the result of option_env! was not fully specified in the
None case, leading to type check failures in the case where the variable
was not defined (e.g. option_env!("FOO").is_none()).
remove more dead code from the old `for`
doc: Add -M and -L option to po4a
doc: Update .pot files
doc: Generate .po files for Japanse translations
tutorial: Add Japanese translation
rustc: Give a hint when a static method call has fewer than expected type parameters

In this case, it's likely to be that the user forgot the `self` type, so
say so.

Closes #4096
Remove unnecessary return
std::at_vec: add benchmarks
Implement formatting arguments for strings and integers

Closes #1651
Define integer formats for all widths

Closes #1653
Correct the padding on integer types for formatting
Explain what ifmt! is all about
librustc: Allow vector repeat exprs in statics.
Add RngUtils::sample() method for reservoir sampling from iterators
Fix freezing of @mut Objects when passing as argument
Reborrow even when passing &Object to &Object, so as to permit freezing
Remove unused automatic cfg bindings Fixes #7169