MD014 - Dollar signs used before commands without showing output
The dollar signs are unnecessary, it is easier to copy and paste and
less noisy if the dollar signs are omitted. Especially when the
command doesn't list the output, but if the command follows output
we can use `$ ` (dollar+space) mainly to differentiate between
command and its ouput.
scenario 1: when command doesn't follow output
```console
cd ~/work
```
scenario 2: when command follow output (use dollar+space)
```console
$ ls ~/work
file1 file2 dir1 dir2 ...
```
Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>