Improve code snippet rendering in README

This converts the code snippets to the alternate block definition and
adds language hints to enable syntax highlighting for compatible parsers
(such as on the GitHub page).

Signed-off-by: Lucas Schwiderski <lucas@lschwiderski.de>

docs/01-readme.md

@@ -8,34 +8,42 @@ Awesome is a highly configurable, next generation framework window manager for X
 
 After extracting the dist tarball, run:
 
-    make
+```sh
+make
+```
 
 This will create a build directory, run `cmake` in it and build Awesome.
 
 After building is finished, you can either install via `make install`:
 
-    make install  # you might need root permissions
+```sh
+make install  # you might need root permissions
+```
 
 or by auto-generating a .deb or .rpm package, for easy removal later on:
 
-    make package
+```sh
+make package
 
-    sudo dpkg -i awesome-x.y.z.deb
-    # or
-    sudo rpm -Uvh awesome-x.y.z.rpm
+sudo dpkg -i awesome-x.y.z.deb
+# or
+sudo rpm -Uvh awesome-x.y.z.rpm
+```
 
 NOTE: Awesome uses [`cmake`](https://cmake.org) to build. In case you want to
 pass arguments to `cmake`, please use the `CMAKE_ARGS` environment variable. For
 instance:
 
-    CMAKE_ARGS="-DCMAKE_INSTALL_PREFIX=/opt/awesome" make
+```sh
+CMAKE_ARGS="-DCMAKE_INSTALL_PREFIX=/opt/awesome" make
+```
 
 
 ### Installing current git master as a package receipts
 
 #### Arch Linux AUR
 
-```
+```sh
 sudo pacman -S --needed base-devel git
 git clone https://aur.archlinux.org/awesome-git.git
 cd awesome-git
@@ -44,7 +52,7 @@ makepkg -fsri
 
 #### Debian-based
 
-```
+```sh
 sudo apt build-dep awesome
 git clone https://github.com/awesomewm/awesome
 cd awesome
@@ -116,12 +124,16 @@ You can directly select Awesome from your display manager. If not, you can
 add the following line to your `.xinitrc` to start Awesome using `startx`
 or to `.xsession` to start Awesome using your display manager:
 
-    exec awesome
+```sh
+exec awesome
+```
 
 In order to connect Awesome to a specific display, make sure that
 the `DISPLAY` environment variable is set correctly, e.g.:
 
-    DISPLAY=foo.bar:1 exec awesome
+```sh
+DISPLAY=foo.bar:1 exec awesome
+```
 
 (This will start Awesome on display `:1` of the host foo.bar.)
 
@@ -145,12 +157,16 @@ problem.
 
 You can call `awesome` with `gdb` like this:
 
-    DISPLAY=:2 gdb awesome
+```sh
+DISPLAY=:2 gdb awesome
+```
 
 Then in `gdb` set any arguments and run it:
 
-    (gdb) set args --replace
-    (gdb) run
+```
+(gdb) set args --replace
+(gdb) run
+```
 
 ## Asking questions