Feature request: enable formatter on lightweight mode

[kkocdko]

Now, in lightweight mode, the formatter is unusable. Formatter is fast and does not need complex code analysis, it's suitable to be enabled in lightweight mode.

Reason: Sometimes we just want to open a single java file on a big project with lightweight mode, enabling formatter will be helpful.

[kkocdko]

Seems that this feature was added to upsteam: eclipse-jdtls/eclipse.jdt.ls#2450

Awesome! Thanks to fbricon

[fbricon]

@kkocdko you can test that feature in the latest pre-release build