Rollup merge of #40496 - projektir:docs_number_headings, r=frewsxcv
Rollup merge of #40496 - projektir:docs_number_headings, r=frewsxcv

Using X headings #39850

Fix for issue #39850, the headings should now be 1, 2, and 3.

graydon/rust,GBGamer/rust,graydon/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,graydon/rust,aidancully/rust,GBGamer/rust,graydon/rust,GBGamer/rust,aidancully/rust,GBGamer/rust