README.md: Fix MD040 warnings

The following warnings are generated by using markdownlint analysis:
```
README.md:5 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
README.md:12 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
README.md:20 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
README.md:29 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
README.md:40 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
README.md:78 MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
```
Refer to markdown-lint [1] to fix MD040
[1]: https://github.com/updownpress/markdown-lint/blob/master/rules/040-fenced-code-language.md

Signed-off-by: George Liu <liuxiwei@ieisystem.com>
Change-Id: Ibb0ba5ad26c7b362258dad92acad48ea10cae9a2
diff --git a/README.md b/README.md
index d16f7f5..68204e0 100644
--- a/README.md
+++ b/README.md
@@ -2,33 +2,25 @@
 
 To build this project, run the following shell commands:
 
-```
-meson setup build
-meson compile -C build
-```
+    meson setup build
+    meson compile -C build
 
 To test:
 
-```
-meson test -C build
-```
+    meson test -C build
 
 ## To Run Server
 
 Running the server requires a serial port (e.g. /dev/ttyS0):
 
-```
-touch obmc-console.conf
-./obmc-console-server --config obmc-console.conf ttyS0
-```
+    touch obmc-console.conf
+    ./obmc-console-server --config obmc-console.conf ttyS0
 
 ## To Connect Client
 
 To connect to the server, simply run the client:
 
-```
-./obmc-console-client
-```
+    ./obmc-console-client
 
 To disconnect the client, use the standard `~.` combination.
 
@@ -37,23 +29,21 @@
 This shows how the host UART connection is abstracted within the BMC as a Unix
 domain socket.
 
-```
-               +---------------------------------------------------------------------------------------------+
-               |                                                                                             |
-               |       obmc-console-client       unix domain socket         obmc-console-server              |
-               |                                                                                             |
-               |     +----------------------+                           +------------------------+           |
-               |     |   client.2200.conf   |  +---------------------+  | server.ttyVUART0.conf  |           |
-           +---+--+  +----------------------+  |                     |  +------------------------+  +--------+-------+
-Network    | 2200 +-->                      +->+ @obmc-console.host0 +<-+                        <--+ /dev/ttyVUART0 |   UARTs
-           +---+--+  | console-id = "host0" |  |                     |  |  console-id = "host0"  |  +--------+-------+
-               |     |                      |  +---------------------+  |                        |           |
-               |     +----------------------+                           +------------------------+           |
-               |                                                                                             |
-               |                                                                                             |
-               |                                                                                             |
-               +---------------------------------------------------------------------------------------------+
-```
+                +---------------------------------------------------------------------------------------------+
+                |                                                                                             |
+                |       obmc-console-client       unix domain socket         obmc-console-server              |
+                |                                                                                             |
+                |     +----------------------+                           +------------------------+           |
+                |     |   client.2200.conf   |  +---------------------+  | server.ttyVUART0.conf  |           |
+            +---+--+  +----------------------+  |                     |  +------------------------+  +--------+-------+
+    Network    | 2200 +-->                      +->+ @obmc-console.host0 +<-+                        <--+ /dev/ttyVUART0 |   UARTs
+            +---+--+  | console-id = "host0" |  |                     |  |  console-id = "host0"  |  +--------+-------+
+                |     |                      |  +---------------------+  |                        |           |
+                |     +----------------------+                           +------------------------+           |
+                |                                                                                             |
+                |                                                                                             |
+                |                                                                                             |
+                +---------------------------------------------------------------------------------------------+
 
 This supports multiple independent consoles. The `console-id` is a unique
 portion for the unix domain socket created by the obmc-console-server instance.
@@ -75,14 +65,11 @@
 The socat command will output names of 2 pty's, one of which is the master and
 the other one is the slave. The master pty can be used to emulate a UART.
 
-```
-$ socat -d -d pty,raw,echo=0,link=pty1 pty,raw,echo=0,link=pty2
+    $ socat -d -d pty,raw,echo=0,link=pty1 pty,raw,echo=0,link=pty2
 
-$ obmc-console-server --console-id dev $(realpath pty2)
+    $ obmc-console-server --console-id dev $(realpath pty2)
 
-$ obmc-console-client -i dev
+    $ obmc-console-client -i dev
 
-# this message should appear for the client
-$ echo "hi" > pty1
-
-```
+    # this message should appear for the client
+    $ echo "hi" > pty1