Update wording of uninitialized value error to be grammatically correct

compiler/src/dotty/tools/dotc/transform/init/Semantic.scala

@@ -1042,7 +1042,7 @@ object Semantic {
 
   /** Utility definition used for better error-reporting of argument errors */
   case class ArgInfo(value: Value, source: Tree) {
-    def promote: Contextual[List[Error]] = value.promote("May only use initialized value as arguments", source)
+    def promote: Contextual[List[Error]] = value.promote("Only initialized values may be used as arguments", source)
   }
 
   /** Evaluate an expression with the given value for `this` in a given class `klass`

tests/init/neg/closureLeak.check

@@ -1,7 +1,7 @@
 -- Error: tests/init/neg/closureLeak.scala:11:14 -----------------------------------------------------------------------
 11 |    l.foreach(a => a.addX(this)) // error
    |              ^^^^^^^^^^^^^^^^^
-   |              Cannot prove that the value is fully-initialized. May only use initialized value as arguments.
+   |             Cannot prove that the value is fully-initialized. Only initialized values may be used as arguments.
    |
-   |              The unsafe promotion may cause the following problem:
-   |              Cannot prove that the value is fully initialized. May only use initialized value as arguments.
+   |             The unsafe promotion may cause the following problem:
+   |             Cannot prove that the value is fully initialized. Only initialized values may be used as arguments.

tests/init/neg/default-this.check

@@ -1,5 +1,5 @@
 -- Error: tests/init/neg/default-this.scala:9:8 ------------------------------------------------------------------------
 9 |        compare() // error
   |        ^^^^^^^
-  |     Cannot prove that the value is fully initialized. May only use initialized value as arguments. Calling trace:
-  |      -> val result = updateThenCompare(5)	[ default-this.scala:11 ]
+  |Cannot prove that the value is fully initialized. Only initialized values may be used as arguments. Calling trace:
+  | -> val result = updateThenCompare(5)	[ default-this.scala:11 ]

tests/init/neg/promotion-loop.check

@@ -1,7 +1,7 @@
 -- Error: tests/init/neg/promotion-loop.scala:16:10 --------------------------------------------------------------------
 16 |  println(b)      // error
    |          ^
-   |          Cannot prove that the value is fully-initialized. May only use initialized value as arguments.
+   |          Cannot prove that the value is fully-initialized. Only initialized values may be used as arguments.
    |
    |          The unsafe promotion may cause the following problem:
-   |          Cannot prove that the value is fully initialized. May only use initialized value as arguments.
+   |          Cannot prove that the value is fully initialized. Only initialized values may be used as arguments.

tests/init/neg/t3273.check

@@ -1,15 +1,15 @@
 -- Error: tests/init/neg/t3273.scala:4:42 ------------------------------------------------------------------------------
 4 |  val num1: LazyList[Int] = 1 #:: num1.map(_ + 1)                        // error
   |                                  ^^^^^^^^^^^^^^^
-  |             Cannot prove that the value is fully-initialized. May only use initialized value as arguments.
+  |             Cannot prove that the value is fully-initialized. Only initialized values may be used as arguments.
   |
   |             The unsafe promotion may cause the following problem:
   |             Access non-initialized value num1. Calling trace:
   |              -> val num1: LazyList[Int] = 1 #:: num1.map(_ + 1)                        // error	[ t3273.scala:4 ]
 -- Error: tests/init/neg/t3273.scala:5:61 ------------------------------------------------------------------------------
 5 |  val num2: LazyList[Int] = 1 #:: num2.iterator.map(_ + 1).to(LazyList)  // error
   |                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-  |             Cannot prove that the value is fully-initialized. May only use initialized value as arguments.
+  |             Cannot prove that the value is fully-initialized. Only initialized values may be used as arguments.
   |
   |             The unsafe promotion may cause the following problem:
   |             Access non-initialized value num2. Calling trace: