Fix various issues with Markdown docs

docs/linux_chromium_arm.md

 # Linux Chromium Arm Recipes
 
 [TOC]
 
 ## Recipe1: Building for an ARM CrOS device
 
 This recipe uses `ninja` (instead of `make`) so its startup time is much lower
 (sub-1s, instead of tens of seconds), is integrated with goma (for
 google-internal users) for very high parallelism, and uses `sshfs` instead of
 `scp` to significantly speed up the compile-run cycle. It has moved to
 https://sites.google.com/a/chromium.org/dev/developers/how-tos/-quickly-building-for-cros-arm-x64
 (mostly b/c of the ease of attaching files to sites).
 
 
 ## Recipe2: Explicit Cross compiling
 
 Due to the lack of ARM hardware with the grunt to build Chromium native, cross
 compiling is currently the recommended method of building for ARM.
 
 These instruction are designed to run on Ubuntu Precise.
 
 ### Installing the toolchain
 
 The install-build-deps script can be used to install all the compiler
 and library dependencies directly from Ubuntu:
 
     $ ./build/install-build-deps.sh
 
-### Installing the rootfs
+### Installing the sysroot
 
-A prebuilt rootfs image is kept up-to-date on Cloud Storage. It will
+A prebuilt sysroot image is kept up-to-date on Cloud Storage. It will
 automatically be installed by gclient runhooks installed if you have
 `target_arch=arm` in your `GYP_DEFINES`.
 
 To install the sysroot manually you can run:
 
     ./chrome/installer/linux/sysroot_scripts/install-debian.wheezy.sysroot.py \
         --arch=arm
 
 ### Building
 
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             Modes "1024x768" "800x600" "640x480"
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 ```
 
 ### Notes
 
 *   To building for thumb reduces the stripped release binary by around 9MB,
     equating to ~33% of the binary size.  To enable thumb, set `'arm_thumb': 1`
 *   TCmalloc does not have an ARM port, so it is disabled.