feat: add guild creation time placeholders to documentation

Author: leo18bernese

docs/guilds/placeholders/placeholderapi.md

@@ -8,19 +8,21 @@ You need to have [PlaceholderAPI](https://www.spigotmc.org/resources/placeholder
 
 :::tip
 To have a Colored TAG use `%guilds_tag_color%` or `%guilds_tag_formatted%` placeholder. You can configure the format in
-the config file.
+the config file.@
 :::
 
-| Placeholder                                      | Description                                | Example                              |
-|--------------------------------------------------|--------------------------------------------|--------------------------------------|
-| `%guilds_name%`                                  | Get the player's guild name                | LeoGuild                             |
-| `%guilds_uuid%`                                  | Get the player's guild uuid                | d8b46fa7-137e-4819-afca-58c5af49c01e |
-| `%guilds_level%`                                 | Get the player's guild level               | 1                                    |
-| `%guilds_xp%`                                    | Get the player's guild experience          | 1000                                 |
-| `%guilds_tag%`                                   | Get the player's guild TAG                 | LeoTag                               |
-| `%guilds_tag_color%` or `%guilds_tag_formatted%` | Tag from config `guild-tag.format` string  | [LeoTag]    <br/>                    |
-| `%guilds_members%`                               | Get the player's guild members SIZE        | 5                                    |
-| `%guilds_online%`                                | Get the player's guild online members SIZE | 3                                    |
+| Placeholder                                      | Description                                    | Example                              |
+|--------------------------------------------------|------------------------------------------------|--------------------------------------|
+| `%guilds_name%`                                  | Get the player's guild name                    | LeoGuild                             |
+| `%guilds_uuid%`                                  | Get the player's guild uuid                    | d8b46fa7-137e-4819-afca-58c5af49c01e |
+| `%guilds_level%`                                 | Get the player's guild level                   | 1                                    |
+| `%guilds_xp%`                                    | Get the player's guild experience              | 1000                                 |
+| `%guilds_tag%`                                   | Get the player's guild TAG                     | LeoTag                               |
+| `%guilds_tag_color%` or `%guilds_tag_formatted%` | Tag from config `guild-tag.format` string      | [LeoTag]    <br/>                    |
+| `%guilds_members%`                               | Get the player's guild members SIZE            | 5                                    |
+| `%guilds_online%`                                | Get the player's guild online members SIZE     | 3                                    |
+| `%guilds_creation_time%`                         | Get the player's guild creation time as long   | 1620000000000                        |
+| `%guilds_creation_time_formatted%`               | Get the player's guild creation time formatted | Sat Mar 28 16:00:00 GMT 2021         |
 
 ### Player Placeholders