fix: indentation after inserting #must_use

Co-authored-by: Lukas Wirth <lukastw97@gmail.com>

Author: feniljain

crates/ide-assists/src/handlers/generate_enum_projection_method.rs

@@ -162,7 +162,7 @@ fn generate_enum_projection_method(
             let field_type_syntax = field_type.syntax();
 
             let must_use = if ctx.config.assist_emit_must_use {
-                "#[must_use]\n"
+                "#[must_use]\n    "
             } else {
                 ""
             };