Rollup merge of #138957 - Natural-selection1:update-Option-doc, r=Amanieu

Update the index of Option to make the summary more comprehensive

fix: #138955

This PR and #138968 are twin PR

By the way, this is my first time contributing to rust, and I'm not a native English speaker, so any suggestions—whether about the wording in the docs or the contribution process itself—would be greatly appreciated!

Author: matthiaskrgr