docs: Minor tweaks to docs/ios_build_instructions.md.

docs/ios_build_instructions.md

 ### Build Instructions (iOS)
 
-**Note:** Upstreaming of iOS code is still a work in progress. In particular, 
+**Note:** Upstreaming of iOS code is still a work in progress. In particular,
 note that **it is not currently possible to build an actual Chromium app.**
 Currently, the buildable binaries are ios\_web\_shell (a minimal wrapper around
 the web layer), and various unit tests.
 
 Prerequisites
 -------------
 
 -   A Mac with a version of OS X capable of running the latest version
     of Xcode.
 -   The latest version of [Xcode](https://developer.apple.com/xcode/),
     including the current iOS SDK.
 -   The current version of the JDK (required for the closure compiler).
 -   [depot\_tools](http://dev.chromium.org/developers/how-tos/install-depot-tools).
 
 Setting Up
 ----------
 
 In the directory where you are going to check out the code, create a
 `chromium.gyp_env` to set the build to use iOS targets (and to use
-hybrid builds; see Building below):
+hybrid builds; see [Building](#Building) below):
 
-`echo "{ 'GYP_DEFINES': 'OS=ios','GYP_GENERATORS':
-'ninja,xcode-ninja', }" > chromium.gyp_env`
+```shell
+cat > chromium.gyp_env <<EOF
+{
+  "GYP_DEFINES": "OS=ios",
+  "GYP_GENERATORS": "ninja,xcode-ninja",
+}
+EOF
+```
 
 If you aren't set up to sign iOS build products via a developer account,
 you should instead use:
 
-`echo "{ 'GYP_DEFINES': 'OS=ios chromium_ios_signing=0', 'GYP_GENERATORS': 'ninja,xcode-ninja', }" > chromium.gyp_env`
+```shell
+cat > chromium.gyp_env <<EOF
+{
+  "GYP_DEFINES": "OS=ios chromium_ios_signing=0",
+  "GYP_GENERATORS": "ninja,xcode-ninja",
+}
+EOF
+```
 
 Also, you should [install API
 keys](https://www.chromium.org/developers/how-tos/api-keys).
 
 Getting the Code
 ----------------
 
 Next, [check out the
-code](https://www.chromium.org/developers/how-tos/get-the-code), with
+code](https://www.chromium.org/developers/how-tos/get-the-code), with:
 
-`fetch ios`
+```shell
+fetch ios
+```
 
 Building
 --------
 
 Build the target you are interested in. The instructions above select
 the ninja/Xcode hybrid mode, which uses ninja to do the actual build,
 but provides a wrapper Xcode project that can be used to build targets
 and navigate the source. (The Xcode project just shells out to ninja to
 do the builds, so you can't actually inspect/change target-level
 settings from within Xcode; this mode avoids generating a large tree of
 Xcode projects, which leads to performance issues in Xcode). To build
 with ninja (simulator and device, respectively):
 
-`ninja -C out/Debug-iphonesimulator All`
+```shell
+ninja -C out/Debug-iphonesimulator All
+ninja -C out/Debug-iphoneos All
+```
 
-`ninja -C out/Debug-iphoneos All`
-
-To build with Xcode, open build/all.ninja.xcworkspace, and choose the
+To build with Xcode, open `build/all.ninja.xcworkspace`, and choose the
 target you want to build.
 
-You should always be able to build all:All, since targets are added
-there for iOS only when they compile.
+You should always be able to build All, since targets are added there for iOS
+only when they compile.
 
 Running
 -------
 
-Any target that is built and runs on the bots (see below) should run
-successfully in a local build. As of the time of writing, this is only
-ios\_web\_shell and unit test targets—see the note at the top of this
-page. Check the bots periodically for updates; more targets (new
-components) will come on line over time.
+Any target that is built and runs on the bots (see [below](#Troubleshooting))
+should run successfully in a local build. As of the time of writing, this is
+only ios\_web\_shell and unit test targets—see the note at the top of this
+page. Check the bots periodically for updates; more targets (new components)
+will come on line over time.
 
 To run in the simulator from the command line, you can use `iossim`. For
-example, to run a debug build of web\_shell:
+example, to run a debug build of ios\_web\_shell:
 
-`out/Debug-iphonesimulator/iossim out/Debug-iphonesimulator/ios_web_shell.app`
+```shell
+out/Debug-iphonesimulator/iossim out/Debug-iphonesimulator/ios_web_shell.app
+```
 
-**Converting an existing Mac checkout into an iOS checkout**
+Converting an existing Mac checkout into an iOS checkout
+--------------------------------------------------------
 
 If you want to convert your Mac checkout into an iOS checkout, you can
-follow the next steps:
+follow those steps:
 
-1- Add 'target\_os = [ "ios" ]' to the bottom of your chromium/.gclient
+1. Add `target_os = [ "ios" ]` to the bottom of your `chromium/.gclient`
 file.
 
-2- Make sure you have the following in your chromium/chromium.gyp\_env
+2. Make sure you have the following in your `chromium/chromium.gyp_env`
 file (removing the `chromium_ios_signing=0` if you want to make
 developer-signed builds):
 
-`{
-"GYP\_DEFINES" : "OS=ios chromium\_ios\_signing=0",
-"GYP\_GENERATORS" : "ninja,xcode-ninja",
-}`
+```json
+{
+  "GYP_DEFINES" : "OS=ios chromium_ios_signing=0",
+  "GYP_GENERATORS" : "ninja,xcode-ninja",
+}
+```
 
-Then make sure you sync again to get all the new files like the
-following. At the end it will run gyp\_chromium which will regenerate
-all the build files according to the new settings.
+Then make sure you sync again to get all the new files like the following. At
+the end it will run `build/gyp_chromium` which will regenerate all the build
+files according to the new settings.
 
-`gclient sync`
+```shell
+gclient sync
+```
 
 Troubleshooting
 ---------------
 
 If your build fails, check the iOS columns of [the Mac
 waterfall](http://build.chromium.org/p/chromium.mac/console) (the last
 two) to see if the bots are green. In general they should be, since
 failures on those bots will close the tree.