Rename files to qmd (#367)

* use qmd file extension

* update filenames in _quarto.yml

* declare knitr engine explicitly in yaml

* specify knitr engine in the document that triggers jupyter

Author: djnavarro

_quarto.yml

@@ -2,6 +2,8 @@ project:
   type: book
   output-dir: _book
 
+engine: knitr
+
 book:
   title: "ggplot2: Elegant Graphics for Data Analysis (3e)"
   reader-mode: true
@@ -19,46 +21,46 @@ book:
   repo-branch: main
   repo-actions: [edit, issue]
   chapters:
-    - index.Rmd
+    - index.qmd
 
-    - preface-3e.Rmd
-    - preface-2e.Rmd
+    - preface-3e.qmd
+    - preface-2e.qmd
 
-    - part: start.Rmd
+    - part: start.qmd
       chapters:
-        - introduction.Rmd
-        - getting-started.Rmd
+        - introduction.qmd
+        - getting-started.qmd
 
-    - part: toolbox.Rmd
+    - part: toolbox.qmd
       chapters:
-        - individual-geoms.Rmd
-        - collective-geoms.Rmd
-        - statistical-summaries.Rmd
-        - maps.Rmd
-        - networks.Rmd
-        - annotations.Rmd
-        - arranging-plots.Rmd
+        - individual-geoms.qmd
+        - collective-geoms.qmd
+        - statistical-summaries.qmd
+        - maps.qmd
+        - networks.qmd
+        - annotations.qmd
+        - arranging-plots.qmd
 
-    - part: scales.Rmd
+    - part: scales.qmd
       chapters:
-        - scales-position.Rmd
-        - scales-colour.Rmd
-        - scales-other.Rmd
+        - scales-position.qmd
+        - scales-colour.qmd
+        - scales-other.qmd
 
-    - part: mastery.Rmd
+    - part: mastery.qmd
       chapters:
-        - layers.Rmd
-        - scales-guides.Rmd
-        - coord.Rmd
-        - facet.Rmd
-        - themes.Rmd
+        - layers.qmd
+        - scales-guides.qmd
+        - coord.qmd
+        - facet.qmd
+        - themes.qmd
 
-    - part: extending.Rmd
+    - part: extending.qmd
       chapters:
-        - programming.Rmd
-        - internals.Rmd
-        - extensions.Rmd
-        - ext-springs.Rmd
+        - programming.qmd
+        - internals.qmd
+        - extensions.qmd
+        - ext-springs.qmd
 
 bibliography: references.bib
 

annotations.Rmd renamed to annotations.qmd

@@ -1,3 +1,7 @@
+---
+engine: knitr
+---
+
 # Preface to the second edition {.unnumbered}
 
 Welcome to the second edition of "ggplot2: elegant graphics for data analysis".