Linebreaks in generics

In testing an upgrade to 1.6.1, we're sometimes seeing line breaks introduced into generics. Seems like this is probably a result of #512. I can see this being useful in pathological cases with extremely long generic type lists, but the issue is that we run prettier with a pretty aggressive line length limit, so we end up seeing split generics even in relatively straight-forward code samples. And it's pretty jarring when you first see it, because as far as I know, splitting generics like this isn't an idiomatic way to format Java (at least I haven't seen it in the wild before).

I tested the prettier-java upgrade on ~1,500 of our internal GitHub repos, and it definitely seemed like, in most cases, this generic splitting was hurting the code readability more than it helped. But curious to get your thoughts on how attached you are to this feature.

**Prettier-Java 1.6.1**

```sh
# Options (if any):
```

**Input:**

```java
public abstract class GenericWblGeneratorWithLongName {

public static PagedResult appendCustomOffsets(
Arg arg1,
Arg arg2
) {
// implementation
}
}
```

**Output:**

```java
public abstract class GenericWblGeneratorWithLongName<
OBJECT_TYPE, RECORD_TYPE
> {

public static <
RECORD, OFFSET
> PagedResult appendCustomOffsets(Arg arg1, Arg arg2) {
// implementation
}
}
```

**Expected behavior:**

```java
public abstract class GenericWblGeneratorWithLongName {

public static PagedResult appendCustomOffsets(
Arg arg1,
Arg arg2
) {
// implementation
}
}
```

Start by reproducing the supplied Java input with the formatter and compare its output with the expected behavior. Trace the formatting path for class and method generic type parameters, then add a regression test for the examples; done means generic lists stay on one line while the existing argument wrapping remains unchanged.

Scritto dal modello di indicizzazione a partire dal testo della issue.