Added spacebar's configuration capability on unique usernames

guide/matrix-vs-discord.md

@@ -81,7 +81,7 @@ Matrix has a handful server implementations and about a dozen general purpose cl
 | ------- | ------- | ------ | ------------------------------------------------|
 | **Registration** | Requires email. Discord may demand your phone number if it detects "suspicious activity." | Depending on homeserver (especially if you're running your own), **email may be optional**, and phone number is usually optional. There is no *automatically enforced* human check after registration. | Depending on instance (especially if you're running your own), **email may be optional**, and phone number is usually optional. There is no *automatically enforced* human check after registration. |
 | Price | Free, with certain features paywalled. | Free for [most homeservers](../../servers) (but please consider donating to them). Hosting a private homeserver may also incur cost (could be [free](https://matrix.org/docs/guides/free-small-matrix-server)). Note that paying (not donation) only affects where your data is hosted and (to a much lesser degree) server performance; it has no effect on features. | Usually free.
-| **Username** | Users are identified by display name (maximum 32 characters) + discriminator (4 randomly-assigned digits) to fellow users, and user IDs (Around 19 digits) for programming purposes. [Twitter-like unique usernames are being rolled out to replace the discriminator system](https://discord.com/blog/usernames). | Users are identified by their email-like ID called MXID (eg. `@alice:example.com`), composed of a username (must be ASCII characters, upper case letters are not allowed) and the server name (not exceeding 255 characters when combined, including the introducing at symbol and the colon separating the parts). A display name can be optionally added (up to ~65200 bytes)[^7]. | Same as Discord.
+| **Username** | Users are identified by display name (maximum 32 characters) + discriminator (4 randomly-assigned digits) to fellow users, and user IDs (Around 19 digits) for programming purposes. [Twitter-like unique usernames are being rolled out to replace the discriminator system](https://discord.com/blog/usernames). | Users are identified by their email-like ID called MXID (eg. `@alice:example.com`), composed of a username (must be ASCII characters, upper case letters are not allowed) and the server name (not exceeding 255 characters when combined, including the introducing at symbol and the colon separating the parts). A display name can be optionally added (up to ~65200 bytes)[^7]. | Same as Discord. Server operators can configure whether to use unique usernames or usernames with discriminators.
 | Avatar | Static, maximum 8 MB. Cannot be zoomed unless using a bot or manually entering the URL to higher definition images, in which case the returned avatar has a maximum definition of 1024x1024. | **See "Attachments" for limits.** Can be zoomed (at least in Element/SchildiChat), in which case the avatar will be shown in the uploaded definition. Animated avatars are **supported**. | Static, up to ~1 MB. Can be zoomed. |
 | Profile description and background | **Supported**. | Not supported currently, will be supported using profile rooms. | Same as Discord. |
 | Ability to read messages while offline | Official web and desktop clients artificially block viewing anything at all when it loses the real-time connection. No such limitation in official mobile clients. | Messages in client cache can be read without restriction. | Currently, the client behaves the same way as Discord's.