Auto merge of #1645 - bryanburgers:download-graph-numbering, r=sgrif
Auto merge of #1645 - bryanburgers:download-graph-numbering, r=sgrif

Use a consistent format for numbers in dl graph

When formatting download numbers in the download graph, use a consistent numbering format for both raw numbers and the rolling 7-day average.

There are cases where the user's local can make inconsistent formatting. Specifically, we use `Number.prototype.toFixed` to format the rolling 7-day average, which always results in a number format that uses a decimal point (e.g. "1234.56"). However, the raw download numbers end up using the locale, which in some places can end up formatting the number with a decimal as the thousands separator ("1.234").

To fix this, use google.visualization.NumberFormat for *both* values, so that they are always consistent.

Fixes #1628

Note that I couldn't fully test this, because even after changing my browser's language to `de`, I would still see English number formatting. I did test it by [forcing the Google Visualization chart locale](https://developers.google.com/chart/interactive/docs/basic_load_libs#loadwithlocale), but I'm still not 100% sure if the numbers will show in a German format for a German viewer.

I am, however, sure that they will always show in a *consistent* format.

rust-lang/crates.io,rust-lang/crates.io,rust-lang/crates.io,rust-lang/crates.io