Add language identifiers to Markdown fenced code blocks

README.md

@@ -24,7 +24,7 @@ JekyllNB is a Jupyter app just like `nbconvert`. Call it with `jupyter jekyllnb`
 The preprocessor reads metadata from your notebook to populate the Jekyll header.
 Add a `jekyll` section to your notebook metadata similar to:
 
-```
+```json
 "jekyll": {
     "layout": "notebook",
     "permalink": "/hello/",
@@ -34,7 +34,7 @@ Add a `jekyll` section to your notebook metadata similar to:
 
 The exporter will add the following header to the generated Markdown:
 
-```
+```text
 ---
 layout: notebook
 permalink: /hello/

docs/layout.md

@@ -5,7 +5,7 @@ By default images are organized into folders for each notebook.
 
 Given a Jupyter notebook `notebook.ipynb`, calling `jekyllnb` will result in the following site layout.
 
-```
+```text
 site-dir
 ├── page-dir
 │   └── notebook.md
@@ -21,7 +21,7 @@ Calling `jupyter jekyllnb --site-dir docs --page-dir _pages --image-dir assets/i
 with the notebook located [here](https://github.com/klane/jekyllnb/blob/master/tests/assets/hello-world.ipynb)
 will result in the following site layout.
 
-```
+```text
 docs
 ├── _pages
 │   └── hello-world.md
@@ -33,7 +33,7 @@ docs
 
 Adding the `--no-auto-folder` flag will place all images in `image-dir`.
 
-```
+```text
 docs
 ├── _pages
 │   └── hello-world.md

docs/multiple-notebooks.md

@@ -3,7 +3,7 @@
 Multiple notebooks can be converted at once using a wildcard.
 Calling `jupyter jekyllnb --site-dir docs --page-dir _pages --image-dir assets/images *.ipynb`
 
-```
+```text
 docs
 ├── _pages
 │   ├── hello-world.md
@@ -20,7 +20,7 @@ docs
 
 Adding the `--no-auto-folder` flag will place all images in `image-dir`.
 
-```
+```text
 docs
 ├── _pages
 │   ├── hello-world.md

docs/nbconvert.md

@@ -5,7 +5,7 @@ You can use the Jekyll exporter with `nbconvert` by calling `jupyter nbconvert -
 
 **Note**: None of the options added by JekyllNB are available with `nbconvert`.
 
-```
+```text
 site-dir
 ├── page-dir
 │   └── notebook.md
@@ -22,7 +22,7 @@ Calling `jupyter nbconvert --to jekyll --output-dir docs/_pages
 with the notebook located [here](https://github.com/klane/jekyllnb/blob/master/tests/assets/hello-world.ipynb)
 will result in the following site layout.
 
-```
+```text
 docs
 └── _pages
     ├── hello-world.md