docs(git): document new revert_icon

Author: cdonnellytx

docs/docs/segment-git.mdx

@@ -72,6 +72,7 @@ An alternative is to use the [Posh-Git segment][poshgit]
 - tag_icon: `string` - icon/text to display before the tag context - defaults to `\uF412`
 - rebase_icon: `string` - icon/text to display before the context when in a rebase - defaults to `\uE728 `
 - cherry_pick_icon: `string` - icon/text to display before the context when doing a cherry-pick - defaults to `\uE29B `
+- revert_icon: `string` - icon/text to display before the context when doing a revert - defaults to `\uF0E2 `
 - merge_icon: `string` icon/text to display before the merge context - defaults to `\uE727 `
 - no_commits_icon: `string` icon/text to display when there are no commits in the repo - defaults to `\uF594 `