[ruby/prism] Fix a token incompatibility for `Prism::Translation::Par…

…ser::Lexer`

This PR fixes a token incompatibility between Parser gem and `Prism::Translation::Parser` for
beginless range:

## Parser gem (Expected)

Returns `tBDOT2` token:

```console
$ bundle exec ruby -Ilib -rparser/ruby33 -ve \
'buf = Parser::Source::Buffer.new("example.rb"); buf.source = "..42"; p Parser::Ruby33.new.tokenize(buf)[2]'
ruby 3.3.0 (2023-12-25 revision ruby/prism@5124f9ac75) [x86_64-darwin22]
[[:tBDOT2, ["..", #<Parser::Source::Range example.rb 0...2>]], [:tINTEGER, [42, #<Parser::Source::Range example.rb 2...4>]]]
```

## `Prism::Translation::Parser` (Actual)

Previously, the parser returned `tDOT2` token when parsing the following:

```console
$ bundle exec ruby -Ilib -rprism -rprism/translation/parser33 -ve \
'buf = Parser::Source::Buffer.new("example.rb"); buf.source = "..42"; p Prism::Translation::Parser33.new.tokenize(buf)[2]'
ruby 3.3.0 (2023-12-25 revision ruby/prism@5124f9ac75) [x86_64-darwin22]
[[:tDOT2, ["..", #<Parser::Source::Range example.rb 0...2>]], [:tINTEGER, [42, #<Parser::Source::Range example.rb 2...4>]]]
```

After the update, the parser now returns `tBDOT2` token for the same input:

```console
$ bundle exec ruby -Ilib -rprism -rprism/translation/parser33 -ve \
'buf = Parser::Source::Buffer.new("example.rb"); buf.source = "..42"; p Prism::Translation::Parser33.new.tokenize(buf)[2]'
ruby 3.3.0 (2023-12-25 revision ruby/prism@5124f9ac75) [x86_64-darwin22]
[[:tBDOT2, ["..", #<Parser::Source::Range example.rb 0...2>]], [:tINTEGER, [42, #<Parser::Source::Range example.rb 2...4>]]]
```

This correction enables the restoration of `endless_range_in_conditional.txt` as a test case.

ruby/prism@f624b99ab0

lib/prism/translation/parser/lexer.rb

@@ -167,7 +167,7 @@ class Lexer
           TILDE: :tTILDE,
           UAMPERSAND: :tAMPER,
           UCOLON_COLON: :tCOLON3,
-          UDOT_DOT: :tDOT2,
+          UDOT_DOT: :tBDOT2,
           UDOT_DOT_DOT: :tBDOT3,
           UMINUS: :tUMINUS,
           UMINUS_NUM: :tUNARY_NUM,

test/prism/parser_test.rb

@@ -73,7 +73,6 @@ class ParserTest < TestCase
     skip_tokens = [
       "comments.txt",
       "constants.txt",
-      "endless_range_in_conditional.txt",
       "heredoc_with_comment.txt",
       "heredoc_with_escaped_newline_at_start.txt",
       "heredocs_leading_whitespace.txt",