Small changes to make type-checking pass

lib/prism/parse_result.rb

@@ -276,13 +276,6 @@ def join(other)
 
       Location.new(source, start_offset, other.end_offset - start_offset)
     end
-
-    # Returns a null location that does not correspond to a source and points to
-    # the beginning of the file. Useful for when you want a location object but
-    # do not care where it points.
-    def self.null
-      new(nil, 0, 0) # steep:ignore
-    end
   end
 
   # This represents a comment that was encountered during parsing. It is the

lib/prism/translation/parser/compiler.rb

@@ -1799,7 +1799,7 @@ def visit_block(call, block)
 
         # Visit a heredoc that can be either a string or an xstring.
         def visit_heredoc(node)
-          children = []
+          children = Array.new
           node.parts.each do |part|
             pushing =
               if part.is_a?(StringNode) && part.unescaped.include?("\n")

sig/prism/parse_result.rbs

@@ -43,8 +43,6 @@ module Prism
     def deconstruct_keys: (Array[Symbol] keys) -> { start_offset: Integer, end_offset: Integer }
     def pretty_print: (untyped q) -> untyped
     def join: (Location other) -> Location
-
-    def self.null: () -> Location
   end
 
   class Comment