docs: add code-hints to builder page

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

docs/reference/commandline/build.md

@@ -65,13 +65,15 @@ a subdirectory inside the repository that will be used as a build context.
 For example, run this command to use a directory called `docker` in the branch
 `container`:
 
+```bash
 $ docker build https://github.com/docker/rootfs.git#container:docker
+```
 
 The following table represents all the valid suffixes with their build
 contexts:
 
 Build Syntax Suffix             | Commit Used           | Build Context Used
---------------------|-------------|-------------------
+--------------------------------|-----------------------|-------------------
 `myrepo.git`                    | `refs/heads/master`   | `/`
 `myrepo.git#mytag`              | `refs/tags/mytag`     | `/`
 `myrepo.git#mybranch`           | `refs/heads/mybranch` | `/`
@@ -85,11 +87,15 @@ Build Syntax Suffix | Commit Used | Build Context Used
 Instead of specifying a context, you can pass a single Dockerfile in the `URL`
 or pipe the file in via `STDIN`. To pipe a Dockerfile from `STDIN`:
 
+```bash
 $ docker build - < Dockerfile
+```
 
 With Powershell on Windows, you can run:
 
+```powershell
 Get-Content Dockerfile | docker build -
+```
 
 If you use STDIN or specify a `URL`, the system places the contents into a file
 called `Dockerfile`, and any `-f`, `--file` option is ignored. In this
@@ -121,7 +127,9 @@ build fails, a non-zero failure code will be returned.
 There should be informational output of the reason for failure output to
 `STDERR`:
 
+```bash
 $ docker build -t fail .
+
 Sending build context to Docker daemon 2.048 kB
 Sending build context to Docker daemon
 Step 1 : FROM busybox
@@ -131,6 +139,7 @@ There should be informational output of the reason for failure output to
 INFO[0000] The command [/bin/sh -c exit 13] returned a non-zero code: 13
 $ echo $?
 1
+```
 
 See also:
 
@@ -140,7 +149,9 @@ See also:
 
 ### Build with PATH
 
+```bash
 $ docker build .
+
 Uploading context 10240 bytes
 Step 1 : FROM busybox
 Pulling repository busybox
@@ -165,6 +176,7 @@ See also:
 Successfully built f52f38b7823e
 Removing intermediate container 9c9e81692ae9
 Removing intermediate container 02071fceb21b
+```
 
 This example specifies that the `PATH` is `.`, and so all the files in the
 local directory get `tar`d and sent to the Docker daemon. The `PATH` specifies
@@ -182,7 +194,9 @@ you must use `--rm=false`. This does not affect the build cache.
 
 ### Build with URL
 
+```bash
 $ docker build github.com/creack/docker-firefox
+```
 
 This will clone the GitHub repository and use the cloned repository as context.
 The Dockerfile at the root of the repository is used as Dockerfile. Note that
@@ -191,21 +205,27 @@ scheme.
 
 ### Build with -
 
+```bash
 $ docker build - < Dockerfile
+```
 
 This will read a Dockerfile from `STDIN` without context. Due to the lack of a
 context, no contents of any local directory will be sent to the Docker daemon.
 Since there is no context, a Dockerfile `ADD` only works if it refers to a
 remote URL.
 
+```bash
 $ docker build - < context.tar.gz
+```
 
 This will build an image for a compressed context read from `STDIN`.  Supported
 formats are: bzip2, gzip and xz.
 
 ### Usage of .dockerignore
 
+```bash
 $ docker build .
+
 Uploading context 18.829 MB
 Uploading context
 Step 1 : FROM busybox
@@ -224,6 +244,7 @@ formats are: bzip2, gzip and xz.
  ---> Using cache
  ---> 99cc1ad10469
 Successfully built 99cc1ad10469
+```
 
 This example shows the use of the `.dockerignore` file to exclude the `.git`
 directory from the context. Its effect can be seen in the changed size of the
@@ -232,7 +253,9 @@ uploaded context. The builder reference contains detailed information on
 
 ### Tag image (-t)
 
+```bash
 $ docker build -t vieux/apache:2.0 .
+```
 
 This will build like the previous example, but it will then tag the resulting
 image. The repository name will be `vieux/apache` and the tag will be `2.0`.
@@ -244,25 +267,32 @@ version.
 For example, to tag an image both as `whenry/fedora-jboss:latest` and
 `whenry/fedora-jboss:v2.1`, use the following:
 
+```bash
 $ docker build -t whenry/fedora-jboss:latest -t whenry/fedora-jboss:v2.1 .
-
+```
 ### Specify Dockerfile (-f)
 
+```bash
 $ docker build -f Dockerfile.debug .
+```
 
 This will use a file called `Dockerfile.debug` for the build instructions
 instead of `Dockerfile`.
 
+```bash
 $ docker build -f dockerfiles/Dockerfile.debug -t myapp_debug .
 $ docker build -f dockerfiles/Dockerfile.prod  -t myapp_prod .
+```
 
 The above commands will build the current build context (as specified by the
 `.`) twice, once using a debug version of a `Dockerfile` and once using a
 production version.
 
+```bash
 $ cd /home/me/myapp/some/dir/really/deep
 $ docker build -f /home/me/myapp/dockerfiles/debug /home/me/myapp
 $ docker build -f ../../../../dockerfiles/debug /home/me/myapp
+```
 
 These two `docker build` commands do the exact same thing. They both use the
 contents of the `debug` file instead of looking for a `Dockerfile` and will use
@@ -302,7 +332,9 @@ A good example is `http_proxy` or source versions for pulling intermediate
 files. The `ARG` instruction lets Dockerfile authors define values that users
 can set at build-time using the  `--build-arg` flag:
 
+```bash
 $ docker build --build-arg HTTP_PROXY=http://10.20.30.2:1234 .
+```
 
 This flag allows you to pass the build-time variables that are
 accessed like regular environment variables in the `RUN` instruction of the