fix Caret arguments ordering (#313)

* fix Caret arguments ordering

`line` was filled with `offset`, `col` was filled with `line` and `offset` with `col`.

I'm guessing at one point Caret was `Caret(offset, line, column)`, but was changed to `Caret(line, column, offset)` without re-examing argument order.

This caused this behavior:

```scala
val p = (Parser.caret.with1 <* Parser.anyChar).rep

val pattern = """aaa"""

val parsed = p.parseAll(pattern).right.get
// parsed: cats.data.NonEmptyList[Caret] = NonEmptyList(Caret(0, 0, 0), List(Caret(1, 0, 1), Caret(2, 0, 2)))
```

Expected:
```scala
// parsed: cats.data.NonEmptyList[Caret] = NonEmptyList(Caret(0, 0, 0), List(Caret(0, 1, 1), Caret(0, 2, 2)))
```

* formatting

* Deconstruct Caret properly

* remove unneeded case

* add assert for offset

Author: hugo-vrijswijk

core/shared/src/main/scala/cats/parse/LocationMap.scala

@@ -69,7 +69,7 @@ class LocationMap(val input: String) {
     */
   def toLineCol(offset: Int): Option[(Int, Int)] =
     if (isValidOffset(offset)) {
-      val Caret(_, line, col) = toCaretUnsafeImpl(offset)
+      val Caret(line, col, _) = toCaretUnsafeImpl(offset)
       Some((line, col))
     } else None
 
@@ -81,9 +81,9 @@ class LocationMap(val input: String) {
       // this is end of line
       if (offset == 0) Caret.Start
       else {
-        val Caret(_, line, col) = toCaretUnsafeImpl(offset - 1)
-        if (endsWithNewLine) Caret(offset, line + 1, 0)
-        else Caret(offset, line, col + 1)
+        val Caret(line, col, _) = toCaretUnsafeImpl(offset - 1)
+        if (endsWithNewLine) Caret(line = line + 1, col = 0, offset = offset)
+        else Caret(line = line, col = col + 1, offset = offset)
       }
     } else {
       val idx = Arrays.binarySearch(firstPos, offset)
@@ -98,10 +98,10 @@ class LocationMap(val input: String) {
         // so we are pointing into a line
         val lineStart = firstPos(line)
         val col = offset - lineStart
-        Caret(offset, line, col)
+        Caret(line = line, col = col, offset = offset)
       } else {
         // idx is exactly the right value because offset is beginning of a line
-        Caret(offset, idx, 0)
+        Caret(line = idx, col = 0, offset = offset)
       }
     }
 

core/shared/src/test/scala/cats/parse/LocationMapTest.scala

@@ -226,7 +226,8 @@ class LocationMapTest extends munit.ScalaCheckSuite {
         val lc = lm.toLineCol(offset)
 
         assertEquals(oc, Some(c))
-        assertEquals(lc, oc.map { case Caret(_, r, c) => (r, c) })
+        assertEquals(lc, oc.map { c => (c.line, c.col) })
+        assertEquals(c.offset, offset)
       }
 
       if (other < 0 || s.length < other) {