feat: add text-to-speech option to members (#570)

Merges PluralKit/PluralKit#570

docs/content/api/models.md

@@ -52,6 +52,7 @@ Every PluralKit entity has two IDs: a short (5-character) ID and a longer UUID.
 |created|?datetime||
 |proxy_tags|array of [ProxyTag objects](#proxytag-object)|
 |keep_proxy|boolean||
+|tts|boolean||
 |autoproxy_enabled|?boolean||
 |message_count|?int||
 |last_message_timestamp|?datetime||

docs/content/command-list.md

@@ -92,6 +92,7 @@ You can have a space after `pk;`, e.g. `pk;system` and `pk; system` will do the
 - `pk;member <member> proxy remove [tags]` - Removes a proxy tag from a member.
 - `pk;member <member> autoproxy [on|off]` - Sets whether a member will be autoproxied when autoproxy is set to latch or front mode.
 - `pk;member <member> keepproxy [on|off]` - Sets whether to include a member's proxy tags in the proxied message.
+- `pk;member <member> tts [on|off]` - Sets whether to send a member's messages as text-to-speech messages.
 - `pk;member <member> pronouns [pronouns]` - Changes the pronouns of a member.
 - `pk;member <member> color [color]` - Changes the color of a member.
 - `pk;member <member> birthdate [birthdate|today]` - Changes the birthday of a member.

docs/content/user-guide.md

@@ -358,6 +358,13 @@ The practical effect of this is:
 * **Keep proxy tags on:** `[Message goes here]` typed -> `[Message goes here]` displayed
 * **Keep proxy tags off:** `[Message goes here]` typed -> `Message goes here` displayed
 
+### Sending text-to-speech messages
+If you'd like your proxied messages to be sent as text-to-speech messages (read off out loud to anyone who has the channel focused) you can enable the text-to-speech option for a given member, like so:
+
+    pk;member John text-to-speech on
+
+Turning the option off is similar - replace "on" with "off" in the command. The default value for every member is off. If you are not allowed to send text-to-speech messages in a server, this feature will not work.
+
 ### Disabling proxying on a per-server basis
 If you need to disable or re-enable proxying messages for your system entirely in a specific server (for example, if you'd like to
 use a different proxy bot there), you can use the commands: