Fix timescale CRLF // comments leaving CR in the token.

TIMESCALE_DIRECTIVE used yyless(yyleng-1), so CRLF comments kept `\r` and the formatter emitted `\r\r\n` (issue #2605).

verible/verilog/parser/verilog-lexer_test.cc

diff --git a/verible/verilog/parser/verilog-lexer_test.cc b/verible/verilog/parser/verilog-lexer_test.cc
index b1f3788..cc18f98 100644
--- a/verible/verilog/parser/verilog-lexer_test.cc
+++ b/verible/verilog/parser/verilog-lexer_test.cc
@@ -2035,6 +2035,23 @@
      {'/', "/"},
      {TK_TimeLiteral, "1ps"},
      {TK_NEWLINE, "\n"}},
+    // Issue #2605: CRLF `//` comments in TIMESCALE_DIRECTIVE must not keep `\r`.
+    {{DR_timescale, "`timescale"},
+     {TK_SPACE, " "},
+     {TK_TimeLiteral, "1ps"},
+     {'/', "/"},
+     {TK_TimeLiteral, "1ps"},
+     {TK_NEWLINE, "\r\n"},
+     {TK_EOL_COMMENT, "// hello"},
+     {TK_NEWLINE, "\r\n"}},
+    {{DR_timescale, "`timescale"},
+     {TK_SPACE, " "},
+     {TK_TimeLiteral, "1ps"},
+     {'/', "/"},
+     {TK_TimeLiteral, "1ps"},
+     {TK_SPACE, " "},
+     {TK_EOL_COMMENT, "// hello"},
+     {TK_NEWLINE, "\r\n"}},
     // TODO(b/134180314): lexer current drops tokens from pragma sections,
     // but instead emit the tokens and filter them out.
     // {{DR_pragma, "`pragma"}, " fragma", {TK_NEWLINE, "\n"}},

verible/verilog/parser/verilog.lex

diff --git a/verible/verilog/parser/verilog.lex b/verible/verilog/parser/verilog.lex
index 759fcc2..5c4cf3b 100644
--- a/verible/verilog/parser/verilog.lex
+++ b/verible/verilog/parser/verilog.lex
@@ -990,7 +990,13 @@
     return TK_COMMENT_BLOCK;
   }
   {EndOfLineComment} {
-    yyless(yyleng-1);  /* return \n to input stream */
+    // Match IN_EOL_COMMENT: CRLF is a two-character terminator. Using
+    // yyless(yyleng-1) left `\r` in the comment token, so the formatter
+    // emitted `\r\r\n` after `timescale comments (issue #2605, PR #2371).
+    if (yyleng >= 2 && yytext[yyleng - 2] == '\r')
+      yyless(yyleng - 2);  /* return \r\n to input stream */
+    else
+      yyless(yyleng - 1);  /* return \n to input stream */
     UpdateLocation();
     return TK_EOL_COMMENT;
   }