Update internals to initializer instead of constructor.

This CL catches up the internals (along with a few error messages) to
say `initializer` instead of `constructor.

Bug: tint:1600
Change-Id: I8e56572c310d77da1130380bdd32b334f27c8e46
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/106462
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Auto-Submit: Dan Sinclair <dsinclair@chromium.org>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>
diff --git a/src/tint/ast/variable.h b/src/tint/ast/variable.h
index ea0ff99..81096e9 100644
--- a/src/tint/ast/variable.h
+++ b/src/tint/ast/variable.h
@@ -47,14 +47,14 @@
     /// @param source the variable source
     /// @param sym the variable symbol
     /// @param type the declared variable type
-    /// @param constructor the constructor expression
+    /// @param initializer the initializer expression
     /// @param attributes the variable attributes
     Variable(ProgramID pid,
              NodeID nid,
              const Source& source,
              const Symbol& sym,
              const ast::Type* type,
-             const Expression* constructor,
+             const Expression* initializer,
              utils::VectorRef<const Attribute*> attributes);
 
     /// Move constructor
@@ -81,8 +81,8 @@
     ///   var i = 1;
     const ast::Type* const type;
 
-    /// The constructor expression or nullptr if none set
-    const Expression* const constructor;
+    /// The initializer expression or nullptr if none set
+    const Expression* const initializer;
 
     /// The attributes attached to this variable
     const utils::Vector<const Attribute*, 2> attributes;