tint: Update constructor / conversion terminology

Rename:
* "type initializer" -> "value constructor"
* "type conversion" -> "value conversion"

Fixed: tint:1848
Change-Id: I3e86a4e944971cea970f0d137641517c36cb807d
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/121060
Auto-Submit: Ben Clayton <bclayton@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: Dan Sinclair <dsinclair@chromium.org>
Kokoro: Kokoro <noreply+kokoro@google.com>
diff --git a/test/tint/array/assign_to_private_var.wgsl b/test/tint/array/assign_to_private_var.wgsl
index 07f05a2..8180341 100644
--- a/test/tint/array/assign_to_private_var.wgsl
+++ b/test/tint/array/assign_to_private_var.wgsl
@@ -23,7 +23,7 @@
 fn foo(src_param : ArrayType) {
   var src_function : ArrayType;
 
-  // Assign from type constructor.
+  // Assign from value constructor.
   dst = ArrayType(vec4(1), vec4(2), vec4(3), vec4(3));
 
   // Assign from parameter.