Fix Rubocop errors

Author: mikeygough

static_docs/class.md

@@ -24,18 +24,24 @@ Classes can include instance methods, class methods, and various types of variab
 
 ```ruby
 class Product
+  # rubocop:disable Style/ClassVars
   # Class variable (shared across all instances)
   @@count = 0
+  # rubocop:enable Style/ClassVars
 
+  # rubocop:disable Style/ClassMethodsDefinitions
   # Class method
   def self.count
     @@count
   end
+  # rubocop:enable Style/ClassMethodsDefinitions
 
   def initialize(name, price)
     @name = name
     @price = price
+    # rubocop:disable Style/ClassVars
     @@count += 1
+    # rubocop:enable Style/ClassVars
   end
 
   # Instance method

static_docs/defined.md

@@ -16,16 +16,14 @@ The `defined?` operator can check various types of expressions and returns diffe
 # Checking different types
 class Example
   CONSTANT = "Hello"
-  @@class_var = "World"
 
   def check_definitions
     @instance_var = "!"
 
-    puts defined?(CONSTANT)     # Output: constant
-    puts defined?(@@class_var)  # Output: class variable
+    puts defined?(CONSTANT) # Output: constant
     puts defined?(@instance_var) # Output: instance-variable
-    puts defined?(yield)        # Output: yield (if block given)
-    puts defined?(super)        # Output: super (if method has super)
+    puts defined?(yield) # Output: yield (if block given)
+    puts defined?(super) # Output: super (if method has super)
   end
 end
 

static_docs/else.md

@@ -18,10 +18,10 @@ end
 The `else` clause can be used with various conditional structures in Ruby.
 
 ```ruby
-# With unless
+# With if (positive condition)
 temperature = 25
 
-unless temperature < 20
+if temperature >= 20
   puts "It's warm"
 else
   puts "It's cool"