New checker: Missing caption in Figure and moire

```
![](files/x.png)
```

```
![     ](files/x.png)
```

```
![  tab   ](files/x.png)
```

```
![  .   ](files/x.png)
```

```
![  ;   ](files/x.png)
```

a correct one may be 
```
![  xxx   ](files/x.png)
```