Update user guide build script path in CI workflows

.github/workflows/docs-and-testcov.yml

@@ -171,7 +171,7 @@ jobs:
       - name: Build user guide
         run: |
           cargo binstall mdbook
-          bash ./build.sh
+          bash ./docs/build.sh
 
       - name: Copy user guide to output directory
         run: |

.github/workflows/run-unit-tests.yml

@@ -82,4 +82,4 @@ jobs:
       - name: Test build user guide
         run: |
           cargo binstall mdbook
-          bash ./build.sh
+          bash ./docs/build.sh