fix: correct MySQL URL format in docs and fix grammar typo

Agent-Logs-Url: https://github.com/DamnCrab/torrust-tracker/sessions/1b7dc46e-9918-4a95-91fe-29c1b375eb8a

Co-authored-by: DamnCrab <42539593+DamnCrab@users.noreply.github.com>

Author: Copilot

packages/configuration/src/v2_0_0/database.rs

@@ -12,7 +12,7 @@ pub struct Database {
     /// Database connection string. The format depends on the database driver.
     /// For `sqlite3`, the format is `path/to/database.db`, for example:
     /// `./storage/tracker/lib/database/sqlite3.db`.
-    /// For `Mysql`, the format is `mysql://db_user:db_user_password:port/db_name`, for
+    /// For `MySQL`, the format is `mysql://db_user:db_user_password@host:port/db_name`, for
     /// example: `mysql://root:password@localhost:3306/torrust`.
     /// For `PostgreSQL`, the format is `postgresql://db_user:db_user_password@host:port/db_name`, for
     /// example: `postgresql://root:password@localhost:5432/torrust`.

packages/tracker-core/src/databases/driver/postgres.rs

@@ -419,7 +419,7 @@ mod tests {
     /*
     We run a PostgreSQL container and run all the tests against the same container and database.
 
-    Test for this driver are executed with:
+    Tests for this driver are executed with:
 
     `TORRUST_TRACKER_CORE_RUN_POSTGRES_DRIVER_TEST=true cargo test`