Add auto review settings and update Fortran instructions

Added auto review settings to .coderabbit.yaml and updated path instructions for Fortran source files.

Author: sbryngelson

.coderabbit.yaml

@@ -3,15 +3,17 @@ language: en-US
 
 reviews:
   profile: chill
+
+  auto_review:
+    enabled: true                  # initial PR-open review
+    auto_incremental_review: false # no re-run on every push
+
   path_instructions:
     - path: "src/**/*.fpp"
       instructions: |
         Fortran source (Fypp-preprocessed). Follow the coding standards in
         docs/documentation/contributing.md and the GPU macro API in
-        docs/documentation/gpuParallelization.md.
-    - path: "src/**/*.f90"
-      instructions: |
-        Fortran source. Follow the coding standards in
+        docs/documentation/gpuParallelization.md and the coding standards in
         docs/documentation/contributing.md.
     - path: "toolchain/**/*.py"
       instructions: |