ruff_db: port concise diagnostic rendering to new renderer

Previously, this was only available in the old renderer.
To avoid regressions, we just copy it to the new renderer.
We don't bother with DRY because the old renderer will be
deleted very soon.

crates/ruff_db/src/diagnostic/render.rs

@@ -13,7 +13,9 @@ use crate::{
     Db,
 };
 
-use super::{Annotation, Diagnostic, DisplayDiagnosticConfig, Severity, SubDiagnostic};
+use super::{
+    Annotation, Diagnostic, DiagnosticFormat, DisplayDiagnosticConfig, Severity, SubDiagnostic,
+};
 
 #[derive(Debug)]
 pub(crate) struct DisplayDiagnostic<'a> {
@@ -45,6 +47,27 @@ impl<'a> DisplayDiagnostic<'a> {
 
 impl std::fmt::Display for DisplayDiagnostic<'_> {
     fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        if matches!(self.config.format, DiagnosticFormat::Concise) {
+            match self.diag.severity() {
+                Severity::Info => f.write_str("info")?,
+                Severity::Warning => f.write_str("warning")?,
+                Severity::Error => f.write_str("error")?,
+                Severity::Fatal => f.write_str("fatal")?,
+            }
+
+            write!(f, "[{rule}]", rule = self.diag.id())?;
+            if let Some(span) = self.diag.primary_span() {
+                write!(f, " {path}", path = self.resolver.path(span.file()))?;
+                if let Some(range) = span.range() {
+                    let input = self.resolver.input(span.file());
+                    let start = input.as_source_code().source_location(range.start());
+                    write!(f, ":{line}:{col}", line = start.row, col = start.column)?;
+                }
+                write!(f, ":")?;
+            }
+            return write!(f, " {message}", message = self.diag.primary_message());
+        }
+
         let resolved = Resolved::new(self.resolver, self.diag);
         let renderable = resolved.to_renderable(self.config.context);
         for diag in renderable.diagnostics.iter() {