README.md: fix all markdownlint warnings

Change-Id: I45d22285c00a6597b83739d4e6ed47c6b6c62beb

Author: telit-fabiopo

README.md

@@ -2,15 +2,16 @@
 
 Find the Linux versions where the commits passed as arguments are available.
 
-When you start the tool the current directory must be a clone of the Linux stable repository:
+When you start the tool the current directory must be a clone of the Linux stable
+repository:
 
-```
+```text
 git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
 ```
 
 E.g.:
 
-```
+```text
 user@host:~$ git clone git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
 user@host:~$ cd linux
 user@host:~$ ~/linux-version-finder/linux-version-finder 22b106e5355d6e7a9c3b5cb5ed4ef22ae585ea94
@@ -19,7 +20,7 @@ v5.4.198 v5.10.121 v5.15.46 v5.17.14 v5.18.3 v5.19-rc1
 
 or the check for multiple commits:
 
-```
+```text
 user@host:~$ ~/linux-version-finder/linux-version-finder 22b106e5355d6e7a9c3b5cb5ed4ef22ae585ea94 2939e1a86f758b55cdba73e29397dd3d94df13bc
 v5.4.198 v5.10.121 v5.15.46 v5.17.14 v5.18.3 v5.19-rc1
 ```
@@ -30,6 +31,6 @@ linux-version-finder --help
 
 ## Linux Install requirements
 
-```
+```text
 pip3 install -r requirements.txt
 ```