User hover shows null when writing the @username

[SKPG-Tech]

When writing the username of someone that doesn't have a name, just a username, the user hover will show null in place of the name.

I happen to look at the code and notice that in the userHoverProvider it doesn't show the hover if the user doesn't have a name, maybe it could still show the hover just replace the null with a space

vscode-pull-request-github/src/issues/userHoverProvider.ts

Line 62 in 8396110

if (user && user.name) {

[meganrogge]

verified via code review