docs: replace var with const in rule examples (#19325)

docs/src/rules/no-prototype-builtins.md

@@ -22,11 +22,11 @@ Examples of **incorrect** code for this rule:
 ```js
 /*eslint no-prototype-builtins: "error"*/
 
-var hasBarProperty = foo.hasOwnProperty("bar");
+const hasBarProperty = foo.hasOwnProperty("bar");
 
-var isPrototypeOfBar = foo.isPrototypeOf(bar);
+const isPrototypeOfBar = foo.isPrototypeOf(bar);
 
-var barIsEnumerable = foo.propertyIsEnumerable("bar");
+const barIsEnumerable = foo.propertyIsEnumerable("bar");
 ```
 
 :::
@@ -38,11 +38,11 @@ Examples of **correct** code for this rule:
 ```js
 /*eslint no-prototype-builtins: "error"*/
 
-var hasBarProperty = Object.prototype.hasOwnProperty.call(foo, "bar");
+const hasBarProperty = Object.prototype.hasOwnProperty.call(foo, "bar");
 
-var isPrototypeOfBar = Object.prototype.isPrototypeOf.call(foo, bar);
+const isPrototypeOfBar = Object.prototype.isPrototypeOf.call(foo, bar);
 
-var barIsEnumerable = {}.propertyIsEnumerable.call(foo, "bar");
+const barIsEnumerable = {}.propertyIsEnumerable.call(foo, "bar");
 ```
 
 :::

docs/src/rules/no-setter-return.md

@@ -33,7 +33,7 @@ Examples of **incorrect** code for this rule:
 ```js
 /*eslint no-setter-return: "error"*/
 
-var foo = {
+const foo = {
     set a(value) {
         this.val = value;
         return value;
@@ -76,7 +76,7 @@ Examples of **correct** code for this rule:
 ```js
 /*eslint no-setter-return: "error"*/
 
-var foo = {
+const foo = {
     set a(value) {
         this.val = value;
     }

docs/src/rules/no-sparse-arrays.md

@@ -10,13 +10,13 @@ further_reading:
 Sparse arrays contain empty slots, most frequently due to multiple commas being used in an array literal, such as:
 
 ```js
-var items = [,,];
+const items = [,,];
 ```
 
 While the `items` array in this example has a `length` of 2, there are actually no values in `items[0]` or `items[1]`. The fact that the array literal is valid with only commas inside, coupled with the `length` being set and actual item values not being set, make sparse arrays confusing for many developers. Consider the following:
 
 ```js
-var colors = [ "red",, "blue" ];
+const colors = [ "red",, "blue" ];
 ```
 
 In this example, the `colors` array has a `length` of 3. But did the developer intend for there to be an empty spot in the middle of the array? Or is it a typo?
@@ -34,8 +34,8 @@ Examples of **incorrect** code for this rule:
 ```js
 /*eslint no-sparse-arrays: "error"*/
 
-var items = [,];
-var colors = [ "red",, "blue" ];
+const items = [,];
+const colors = [ "red",, "blue" ];
 ```
 
 :::
@@ -47,11 +47,11 @@ Examples of **correct** code for this rule:
 ```js
 /*eslint no-sparse-arrays: "error"*/
 
-var items = [];
-var items = new Array(23);
+const items = [];
+const arr = new Array(23);
 
 // trailing comma (after the last element) is not a problem
-var colors = [ "red", "blue", ];
+const colors = [ "red", "blue", ];
 ```
 
 :::

docs/src/rules/no-undef.md

@@ -22,8 +22,8 @@ Examples of **incorrect** code for this rule:
 ```js
 /*eslint no-undef: "error"*/
 
-var foo = someFunction();
-var bar = a + 1;
+const foo = someFunction();
+const bar = a + 1;
 ```
 
 :::
@@ -36,8 +36,8 @@ Examples of **correct** code for this rule with `global` declaration:
 /*global someFunction, a*/
 /*eslint no-undef: "error"*/
 
-var foo = someFunction();
-var bar = a + 1;
+const foo = someFunction();
+const bar = a + 1;
 ```
 
 :::

docs/src/rules/no-unexpected-multiline.md

@@ -31,20 +31,20 @@ Examples of **incorrect** code for this rule:
 ```js
 /*eslint no-unexpected-multiline: "error"*/
 
-var foo = bar
+const foo = bar
 (1 || 2).baz();
 
-var hello = 'world'
+const hello = 'world'
 [1, 2, 3].forEach(addNumber);
 
-let x = function() {}
+const x = function() {}
 `hello`
 
-let y = function() {}
+const y = function() {}
 y
 `hello`
 
-let z = foo
+const z = foo
 /regex/g.test(bar)
 ```
 
@@ -57,22 +57,22 @@ Examples of **correct** code for this rule:
 ```js
 /*eslint no-unexpected-multiline: "error"*/
 
-var foo = bar;
+const foo = bar;
 (1 || 2).baz();
 
-var foo = bar
+const baz = bar
 ;(1 || 2).baz()
 
-var hello = 'world';
+const hello = 'world';
 [1, 2, 3].forEach(addNumber);
 
-var hello = 'world'
+const hi = 'world'
 void [1, 2, 3].forEach(addNumber);
 
-let x = function() {};
+const x = function() {};
 `hello`
 
-let tag = function() {}
+const tag = function() {}
 tag `hello`
 ```