Rename build_view to new_view and build_model to new_model

The word "new" is shorter and blends in with `new` constructors that are common
in Rust. Been meaning to do this for a while.

crates/semantic_index2/src/semantic_index.rs

@@ -341,7 +341,7 @@ impl SemanticIndex {
             t0.elapsed().as_millis()
         );
 
-        cx.build_model(|cx| {
+        cx.new_model(|cx| {
             let t0 = Instant::now();
             let embedding_queue =
                 EmbeddingQueue::new(embedding_provider.clone(), cx.background_executor().clone());