Use 'scheme' instead of 'prefix' in DATABASE_URL messages

Per review feedback, 'scheme' is the more accurate term for the
sqlite:// portion of the URL.

.env.template

@@ -50,9 +50,9 @@
 #########################
 
 ## Database URL
-## When using SQLite, this should use the sqlite:// prefix followed by the path
+## When using SQLite, this should use the sqlite:// scheme followed by the path
 ## to the DB file. It defaults to sqlite://%DATA_FOLDER%/db.sqlite3.
-## Bare paths without the sqlite:// prefix are supported for backwards compatibility,
+## Bare paths without the sqlite:// scheme are supported for backwards compatibility,
 ## but only if the database file already exists.
 # DATABASE_URL=sqlite://data/db.sqlite3
 ## When using MySQL, specify an appropriate connection URI.

src/db/mod.rs

@@ -291,7 +291,7 @@ impl DbConnType {
                 err!(format!(
                     "`DATABASE_URL` does not match any known database scheme (mysql://, postgresql://, sqlite://) \
                      and no existing SQLite database was found at '{url}'. \
-                     If you intend to use SQLite, use an explicit `sqlite://` prefix in your `DATABASE_URL`. \
+                     If you intend to use SQLite, use an explicit `sqlite://` scheme in your `DATABASE_URL`. \
                      Otherwise, check your DATABASE_URL for typos or quoting issues."
                 ))
             }