docs(building-from-source): suggest optimized install cmd as alternative (#13553)

book/src/building-from-source.md

@@ -35,10 +35,19 @@ RUSTFLAGS="-C target-feature=-crt-static"
 2. Compile from source:
 
    ```sh
+   # Reproducible
    cargo install --path helix-term --locked
    ```
+   ```sh
+   # Optimized
+   cargo install \
+      --profile opt \
+      --config 'build.rustflags="-C target-cpu=native"' \
+      --path helix-term \
+      --locked
+   ```
 
-   This command will create the `hx` executable and construct the tree-sitter
+   Either command will create the `hx` executable and construct the tree-sitter
    grammars in the local `runtime` folder.
 
 > 💡 If you do not want to fetch or build grammars, set an environment variable `HELIX_DISABLE_AUTO_GRAMMAR_BUILD`