docs: fix syntax highlighting of code blocks

And various other cleanups

Change-Id: I240badc5358c09f006c2a22d4706ce373f2dd188
diff --git a/docs/INSTALL.rst b/docs/INSTALL.rst
index 18b4e26..d9de1cb 100644
--- a/docs/INSTALL.rst
+++ b/docs/INSTALL.rst
@@ -75,7 +75,7 @@
 *ndn-cxx* library. If you do not want a development version of NFD, make sure you
 checkout the correct release tag (e.g., ``*-0.7.0``) from both repositories.
 
-::
+.. code-block:: sh
 
     # Download ndn-cxx
     git clone https://github.com/named-data/ndn-cxx.git
@@ -97,11 +97,15 @@
 
 On Linux, NFD needs the following dependencies to enable optional features:
 
-- On Ubuntu::
+- On **Ubuntu**:
+
+  .. code-block:: sh
 
     sudo apt install libpcap-dev libsystemd-dev
 
-- On CentOS and Fedora::
+- On **CentOS** and **Fedora**:
+
+  .. code-block:: sh
 
     sudo dnf config-manager --enable PowerTools  # on CentOS only
     sudo dnf install libpcap-devel systemd-devel
@@ -109,7 +113,9 @@
 Build
 ~~~~~
 
-The following commands can be used to build and install NFD from source::
+The following commands can be used to build and install NFD from source:
+
+.. code-block:: sh
 
     ./waf configure  # on CentOS, add --without-pch
     ./waf
@@ -117,7 +123,9 @@
 
 If you have installed ndn-cxx and/or any other dependencies into a non-standard path,
 you may need to modify the ``PKG_CONFIG_PATH`` environment variable before running
-``./waf configure``. For example::
+``./waf configure``. For example:
+
+.. code-block:: sh
 
     export PKG_CONFIG_PATH="/custom/lib/pkgconfig:$PKG_CONFIG_PATH"
     ./waf configure
@@ -141,7 +149,7 @@
 The following example shows how to completely disable debug symbols and configure
 NFD to be installed into ``/usr`` with configuration in the ``/etc`` directory.
 
-::
+.. code-block:: sh
 
     CXXFLAGS="-O2" ./waf configure --prefix=/usr --sysconfdir=/etc
     ./waf
@@ -154,14 +162,18 @@
 
 To build NFD with a different compiler (rather than the platform default), set the
 ``CXX`` environment variable to point to the compiler binary. For example, to build
-with clang on Linux, use the following::
+with clang on Linux, use the following:
+
+.. code-block:: sh
 
     CXX=clang++ ./waf configure
 
 Building the documentation
 ~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-Tutorials and API documentation can be built using the following commands::
+Tutorials and API documentation can be built using the following commands:
+
+.. code-block:: sh
 
     # Full set of documentation (tutorials + API) in build/docs
     ./waf docs