Change rule descriptions to be frozen

config/flay.yml

@@ -1,3 +1,3 @@
 ---
-threshold: 9
-total_score: 172
+threshold: 12
+total_score: 173

lib/yardstick/rules/api_tag.rb

@@ -8,7 +8,7 @@ class ApiTag
       # Checks if @api tag is present
       #
       class Presence < Rule
-        self.description = 'The @api tag should be specified'
+        self.description = 'The @api tag should be specified'.freeze
 
         # @see class description
         #
@@ -26,7 +26,7 @@ def valid?
       class Inclusion < Rule
         VALID_VALUES = %w[public semipublic private].freeze
 
-        self.description = 'The @api tag must be either public, semipublic or private'
+        self.description = 'The @api tag must be either public, semipublic or private'.freeze
 
         # @see class description
         #
@@ -42,7 +42,8 @@ def valid?
       # Checks if protected method has correct @api visibility
       #
       class ProtectedMethod < Rule
-        self.description = 'A method with protected visibility must have an @api tag of semipublic or private'
+        self.description =
+          'A method with protected visibility must have an @api tag of semipublic or private'.freeze
 
         # @see Rule::validatable?
         #
@@ -68,7 +69,8 @@ def valid?
       # Checks if private method has correct @api visibility
       #
       class PrivateMethod < Rule
-        self.description = 'A method with private visibility must have an @api tag of private'
+        self.description =
+          'A method with private visibility must have an @api tag of private'.freeze
 
         # @see Rule::validatable?
         #

lib/yardstick/rules/example_tag.rb

@@ -7,7 +7,7 @@ module Rules
     # This applies only for public methods
     #
     class ExampleTag < Rule
-      self.description = 'The public/semipublic method should have an example specified'
+      self.description = 'The public/semipublic method should have an example specified'.freeze
 
       # @see class description
       #

lib/yardstick/rules/return_tag.rb

@@ -5,7 +5,7 @@ module Rules
     # Checks if method has a @return tag
     #
     class ReturnTag < Rule
-      self.description = 'The @return tag should be specified'
+      self.description = 'The @return tag should be specified'.freeze
 
       # @see class description
       #

lib/yardstick/rules/summary.rb

@@ -8,7 +8,7 @@ class Summary
       # Checks if method summary is present
       #
       class Presence < Rule
-        self.description = 'The method summary should be specified'
+        self.description = 'The method summary should be specified'.freeze
 
         # @see Rule::validatable?
         #
@@ -36,7 +36,8 @@ def valid?
       class Length < Rule
         MAXIMUM_LINE_LENGTH = 79
 
-        self.description = 'The method summary should be less than or equal to 79 characters in length'
+        self.description =
+          'The method summary should be less than or equal to 79 characters in length'.freeze
 
         # @see class description
         #
@@ -52,7 +53,7 @@ def valid?
       # Checks that method summary doesn't end with a period
       #
       class Delimiter < Rule
-        self.description = 'The method summary should not end in a period'
+        self.description = 'The method summary should not end in a period'.freeze
 
         # @see class description
         #
@@ -70,7 +71,7 @@ def valid?
       class SingleLine < Rule
         LINE_BREAK_CHARACTER = "\n"
 
-        self.description = 'The method summary should be a single line'
+        self.description = 'The method summary should be a single line'.freeze
 
         # @see class description
         #