refactor: convert IO from singleton instance to static class with metaclass native methods

Replace the global `io` singleton object with a static `IO` class, moving the `write` native from the instance to the metaclass. Update all benchmark, example, and test files to use `IO.write()` instead of `io.write()`.

test/string/contains.wren

@@ -1,8 +1,8 @@
-io.write("".contains(""))              // expect: true
-io.write("anything".contains(""))      // expect: true
-io.write("something".contains("meth")) // expect: true
-io.write("something".contains("some")) // expect: true
-io.write("something".contains("ing"))  // expect: true
-io.write("something".contains("math")) // expect: false
+IO.write("".contains(""))              // expect: true
+IO.write("anything".contains(""))      // expect: true
+IO.write("something".contains("meth")) // expect: true
+IO.write("something".contains("some")) // expect: true
+IO.write("something".contains("ing"))  // expect: true
+IO.write("something".contains("math")) // expect: false
 
 // TODO: Passing non-string as argument.

test/string/count.wren

@@ -1,2 +1,2 @@
-io.write("".count)   // expect: 0
-io.write("a string".count) // expect: 8
+IO.write("".count)   // expect: 0
+IO.write("a string".count) // expect: 8

test/string/equality.wren

@@ -1,19 +1,19 @@
-io.write("" == "")          // expect: true
-io.write("abcd" == "abcd")  // expect: true
-io.write("abcd" == "d")     // expect: false
-io.write("e" == "abcd")     // expect: false
-io.write("" == "abcd")      // expect: false
+IO.write("" == "")          // expect: true
+IO.write("abcd" == "abcd")  // expect: true
+IO.write("abcd" == "d")     // expect: false
+IO.write("e" == "abcd")     // expect: false
+IO.write("" == "abcd")      // expect: false
 
 // Not equal to other types.
-io.write("1" == 1)        // expect: false
-io.write("true" == true)  // expect: false
+IO.write("1" == 1)        // expect: false
+IO.write("true" == true)  // expect: false
 
-io.write("" != "")          // expect: false
-io.write("abcd" != "abcd")  // expect: false
-io.write("abcd" != "d")     // expect: true
-io.write("e" != "abcd")     // expect: true
-io.write("" != "abcd")      // expect: true
+IO.write("" != "")          // expect: false
+IO.write("abcd" != "abcd")  // expect: false
+IO.write("abcd" != "d")     // expect: true
+IO.write("e" != "abcd")     // expect: true
+IO.write("" != "abcd")      // expect: true
 
 // Not equal to other types.
-io.write("1" != 1)        // expect: true
-io.write("true" != true)  // expect: true
+IO.write("1" != 1)        // expect: true
+IO.write("true" != true)  // expect: true

test/string/escapes.wren

@@ -1,7 +1,7 @@
 // Escape characters.
-io.write("\"")     // expect: "
-io.write("\\")     // expect: \
-io.write("(\n)")   // expect: (
+IO.write("\"")     // expect: "
+IO.write("\\")     // expect: \
+IO.write("(\n)")   // expect: (
                    // expect: )
 
 // TODO: Non-printing escapes like \t.

test/string/literals.wren

@@ -1,2 +1,2 @@
-io.write("".count)   // expect: 0
-io.write("a string") // expect: a string
+IO.write("".count)   // expect: 0
+IO.write("a string") // expect: a string

test/string/subscript.wren

@@ -1,24 +1,24 @@
 // Returns characters (as strings).
-io.write("abcd"[0]) // expect: a
-io.write("abcd"[1]) // expect: b
-io.write("abcd"[2]) // expect: c
-io.write("abcd"[3]) // expect: d
+IO.write("abcd"[0]) // expect: a
+IO.write("abcd"[1]) // expect: b
+IO.write("abcd"[2]) // expect: c
+IO.write("abcd"[3]) // expect: d
 
 // Allows indexing backwards from the end.
-io.write("abcd"[-4]) // expect: a
-io.write("abcd"[-3]) // expect: b
-io.write("abcd"[-2]) // expect: c
-io.write("abcd"[-1]) // expect: d
+IO.write("abcd"[-4]) // expect: a
+IO.write("abcd"[-3]) // expect: b
+IO.write("abcd"[-2]) // expect: c
+IO.write("abcd"[-1]) // expect: d
 
 // Handle out of bounds.
 // TODO: Should halt the fiber or raise an error somehow.
-io.write("abcd"[4])  // expect: null
-io.write("abcd"[-5]) // expect: null
+IO.write("abcd"[4])  // expect: null
+IO.write("abcd"[-5]) // expect: null
 
 // Handle wrong argument type.
 // TODO: Should halt the fiber or raise an error somehow.
-io.write("abcd"[true]) // expect: null
+IO.write("abcd"[true]) // expect: null
 
 // Handle non-integer index.
 // TODO: Should halt the fiber or raise an error somehow.
-io.write("abcd"[1.5]) // expect: null
+IO.write("abcd"[1.5]) // expect: null

test/string/to_string.wren

@@ -1,2 +1,2 @@
-io.write("".toString == "") // expect: true
-io.write("blah".toString == "blah") // expect: true
+IO.write("".toString == "") // expect: true
+IO.write("blah".toString == "blah") // expect: true

test/string/type.wren

@@ -1,4 +1,4 @@
-io.write("s" is String)      // expect: true
-io.write("s" is Object)      // expect: true
-io.write("s" is Num)         // expect: false
-io.write("s".type == String) // expect: true
+IO.write("s" is String)      // expect: true
+IO.write("s" is Object)      // expect: true
+IO.write("s" is Num)         // expect: false
+IO.write("s".type == String) // expect: true