Execute pipes line by line in fsi

**Is your feature request related to a problem? Please describe.**

When writing pipelines in fsi, they have to be executed as a single unit:
```
1 values
2 |> fun1
3 |> fun2
```
You need to select lines 1 to 3 to execute it, but you cannot execute line 1, then 2, then 3.

**Describe the solution you'd like**

It would give more flexibility to execute lines one by one.
When a line starts with |>, it would interpret it as
```
it |> fun1
```
Executing the previous script line by line would be interpreted as:
```
let it = values
let it = it |> fun1
let it = it |> fun2
```

**Describe alternatives you've considered**

Continue to select multiple lines, but it's easy to forget and get an error at execution.