Rename tokens to lexemes in pipeline expressions

lib/gitlab/ci/pipeline/expression/equals.rb

@@ -2,7 +2,7 @@ module Gitlab
   module Ci
     module Pipeline
       module Expression
-        class Equals < Expression::Token
+        class Equals < Expression::Lexeme
           PATTERN = /==/.freeze
 
           def initialize(left, right)

lib/gitlab/ci/pipeline/expression/token.rb → lib/gitlab/ci/pipeline/expression/lexeme.rb

@@ -2,15 +2,11 @@ module Gitlab
   module Ci
     module Pipeline
       module Expression
-        class Token
+        class Lexeme
           def evaluate(**variables)
             raise NotImplementedError
           end
 
-          def self.build(string)
-            raise NotImplementedError
-          end
-
           def self.scan(scanner)
             scanner.scan(PATTERN)
           end

lib/gitlab/ci/pipeline/expression/null.rb

@@ -2,7 +2,7 @@ module Gitlab
   module Ci
     module Pipeline
       module Expression
-        class Null < Expression::Token
+        class Null < Expression::Lexeme
           PATTERN = /null/.freeze
 
           def initialize(value)

lib/gitlab/ci/pipeline/expression/string.rb

@@ -2,7 +2,7 @@ module Gitlab
   module Ci
     module Pipeline
       module Expression
-        class String < Expression::Token
+        class String < Expression::Lexeme
           PATTERN = /("|')(?<value>.+)('|")/.freeze
 
           def initialize(value)

lib/gitlab/ci/pipeline/expression/variable.rb

@@ -2,7 +2,7 @@ module Gitlab
   module Ci
     module Pipeline
       module Expression
-        class Equality < Expression::Token
+        class Equality < Expression::Lexeme
           PATTERN = /$(?<name>\w+)/.freeze
 
           def initialize(value)