docs: add missing backticks to id-length (#19217)

Author: lumirlumir

docs/src/rules/id-length.md

@@ -100,8 +100,8 @@ data["y"] = 3;  // excused because of calculated property access
 
 This rule has an object option:
 
-* `"min"` (default: 2) enforces a minimum identifier length
-* `"max"` (default: Infinity) enforces a maximum identifier length
+* `"min"` (default: `2`) enforces a minimum identifier length
+* `"max"` (default: `Infinity`) enforces a maximum identifier length
 * `"properties": always` (default) enforces identifier length convention for property names
 * `"properties": never` ignores identifier length convention for property names
 * `"exceptions"` allows an array of specified identifier names