Use the talk path instead of just the name

Pass the path to the talk directory - e.g.
`just generate ./src/test-driven-drupal` instead of just the talk
name/slug.

This doesn't change where the files are sourced from or output, but this
makes it easier to use `just generate` as I can use tab completion when
executing the command - making it quicker and less prone to typos.

justfile

@@ -13,19 +13,26 @@ clean:
     -type f \( -name "{{ pdf_filename }}" -o -name *.build_temp -o -name {{ thumbnail_filename }} \) \
     -delete
 
-generate name: (generate-pdf name)
+generate talk_path: (generate-pdf talk_path)
 
-generate-pdf name:
+generate-pdf talk_path:
-  cd src/{{ name }} && rst2pdf {{ rst_filename }} \
+  #!/usr/bin/env bash
+  set -o errexit
+  set -o nounset
+
+  talk_slug=$(basename {{ talk_path }})
+
+  pushd "{{ talk_path }}"
+
+  rst2pdf {{ rst_filename }} \
     --break-level 1 \
     -e preprocess \
     --fit-background-mode scale \
     --font-path ../fonts \
-    --output ../../dist/{{ name }}.pdf \
+    --output "../../dist/${talk_slug}.pdf" \
     --stylesheets opdavies-light,tango \
     --stylesheet-path ../styles
 
-  tree dist
+  popd
 
-present name:
+  tree dist
-  pdfpc "dist/{{ name }}.pdf"