Start offset for diagnostics should point to start of position

[olafurpg]

object A {
  "".lengthCompare("1".substring(0))
}

In BSP, Bloop reports the following range position for the diagnostic

a/src/main/scala/A.scala:2:33: error: type mismatch;
 found   : String
 required: Int
  "".lengthCompare("1".substring(0))
                                ^^^

I expected the range position to be the following

a/src/main/scala/A.scala:2:33: error: type mismatch;
 found   : String
 required: Int
  "".lengthCompare("1".substring(0))
                   ^^^^^^^^^^^^^^^^

It looks like the start offset is using the Position.point offset from the compiler instead of Position.start. Here is how the error looks from scalac in the terminal with -Yrangepos enabled

err.scala:2: error: type mismatch;
 found   : String
 required: Int
      def a = "".lengthCompare("1".substring(1))
                                            ^
one error found

In mdoc, we use Position.{start,end} from the compiler diagnostics and the errors are published as expected.

info: Compiling 1 file to /Users/olafurpg/dev/metals/target/out
error: /Users/olafurpg/dev/metals/target/docs/in.md:2:28: type mismatch;
 found   : String
 required: Int
  def a = "".lengthCompare("1".substring(1))
                           ^^^^^^^^^^^^^^^^
info: Compiled in 1.28s (1 error)

[olafurpg]

Here is how the error looks in vscode with Metals

[olafurpg]

Another test case: val x: Int = "a" + "b" produces the following position currently

I expect the position to start at "a"

error: /Users/olafurpg/dev/metals/target/docs/in.md:2:16: type mismatch;
 found   : String("ab")
 required: Int
  val x: Int = "a" + "b"
               ^^^^^^^^^