Use tripleslash file:/// URIs uniformly. Avoid null text in TextEdits.

[sdedic]

The PR provides two small fixes:

• Utils.toUri returns file:///path/somewhere URIs even though native translation returns "file:/path/somewhere". Incoming URIs seem to use file:/// consistently, so we should do as well, so they can compare as strings
• When converting from lsp API TextEdit to lsp4j protocol structure, make sure that the text property is always non-null

[lahodaj]

I think I would appreciate more details on the tricks played for Windows URIs - what exactly is the purpose? Thanks!

[sdedic]

I think I would appreciate more details on the tricks played for Windows URIs - what exactly is the purpose? Thanks!

Windows URLs, which are not network mounts (file://hostname/mount/path) use file:/C:/path (where "C" is the drive letter). As the code tries to replace everything which starts with file: except file:///, I wanted to avoid damaging file:/C:/path URIs. That's all.

[lahodaj]

Looks good to me.