Don't put dockerfiles in one continuous code block

Signed-off-by: Aidan Hobson Sayers <aidanhs@cantab.net>

docs/reference/builder.md

@@ -1166,45 +1166,50 @@ or a signal name in the format SIGNAME, for instance SIGKILL.
 
 ## Dockerfile examples
 
-    # Nginx
-    #
-    # VERSION               0.0.1
-
-    FROM      ubuntu
-    MAINTAINER Victor Vieux <victor@docker.com>
-
-    LABEL Description="This image is used to start the foobar executable" Vendor="ACME Products" Version="1.0"
-    RUN apt-get update && apt-get install -y inotify-tools nginx apache2 openssh-server
-
-    # Firefox over VNC
-    #
-    # VERSION               0.3
-
-    FROM ubuntu
+```
+# Nginx
+#
+# VERSION               0.0.1
 
-    # Install vnc, xvfb in order to create a 'fake' display and firefox
-    RUN apt-get update && apt-get install -y x11vnc xvfb firefox
-    RUN mkdir ~/.vnc
-    # Setup a password
-    RUN x11vnc -storepasswd 1234 ~/.vnc/passwd
-    # Autostart firefox (might not be the best way, but it does the trick)
-    RUN bash -c 'echo "firefox" >> /.bashrc'
+FROM      ubuntu
+MAINTAINER Victor Vieux <victor@docker.com>
 
-    EXPOSE 5900
-    CMD    ["x11vnc", "-forever", "-usepw", "-create"]
+LABEL Description="This image is used to start the foobar executable" Vendor="ACME Products" Version="1.0"
+RUN apt-get update && apt-get install -y inotify-tools nginx apache2 openssh-server
+```
 
-    # Multiple images example
-    #
-    # VERSION               0.1
+```
+# Firefox over VNC
+#
+# VERSION               0.3
+
+FROM ubuntu
+
+# Install vnc, xvfb in order to create a 'fake' display and firefox
+RUN apt-get update && apt-get install -y x11vnc xvfb firefox
+RUN mkdir ~/.vnc
+# Setup a password
+RUN x11vnc -storepasswd 1234 ~/.vnc/passwd
+# Autostart firefox (might not be the best way, but it does the trick)
+RUN bash -c 'echo "firefox" >> /.bashrc'
+
+EXPOSE 5900
+CMD    ["x11vnc", "-forever", "-usepw", "-create"]
+```
 
-    FROM ubuntu
-    RUN echo foo > bar
-    # Will output something like ===> 907ad6c2736f
+```
+# Multiple images example
+#
+# VERSION               0.1
 
-    FROM ubuntu
-    RUN echo moo > oink
-    # Will output something like ===> 695d7793cbe4
+FROM ubuntu
+RUN echo foo > bar
+# Will output something like ===> 907ad6c2736f
 
-    # You᾿ll now have two images, 907ad6c2736f with /bar, and 695d7793cbe4 with
-    # /oink.
+FROM ubuntu
+RUN echo moo > oink
+# Will output something like ===> 695d7793cbe4
 
+# You᾿ll now have two images, 907ad6c2736f with /bar, and 695d7793cbe4 with
+# /oink.
+```