Restore AdjustColumnUsingTokenSpacing for EOL comment column calc

Move tokens lookup before the loop and factor spacing logic back into
AdjustColumnUsingTokenSpacing with the #2542 newline-aware preserve fix
(PR review feedback).

verible/verilog/formatting/formatter.cc

diff --git a/verible/verilog/formatting/formatter.cc b/verible/verilog/formatting/formatter.cc
index 8384bef..9bd3dd2 100644
--- a/verible/verilog/formatting/formatter.cc
+++ b/verible/verilog/formatting/formatter.cc
@@ -741,6 +741,37 @@
     return column;
   }
 
+  static void AdjustColumnUsingTokenSpacing(
+      const verible::FormattedToken &token, int *column) {
+    switch (token.before.action) {
+      case verible::SpacingDecision::kPreserve: {
+        if (token.before.preserved_space_start !=
+            verible::string_view_null_iterator()) {
+          const std::string_view leading = token.OriginalLeadingSpaces();
+          const auto last_nl = leading.find_last_of('\n');
+          if (last_nl == std::string_view::npos) {
+            *column += leading.length();
+          } else {
+            // Reset column after the last newline, same as FormattedToken
+            // emit (GitHub issue 2542).
+            *column = static_cast<int>(leading.length() - last_nl - 1);
+          }
+        } else {
+          *column += token.before.spaces;
+        }
+        break;
+      }
+      case verible::SpacingDecision::kWrap:
+        // Newline then only the wrap indent (same as FormattedToken emit).
+        *column = token.before.spaces;
+        break;
+      case verible::SpacingDecision::kAlign:
+      case verible::SpacingDecision::kAppend:
+        *column += token.before.spaces;
+        break;
+    }
+  }
+
   static int CalculateEolCommentColumn(const verible::FormattedExcerpt &line) {
     // Compute the starting column of the trailing EOL comment the same way
     // FormattedExcerpt::FormattedText emits spaces, including:
@@ -752,8 +783,7 @@
     if (line.Tokens().empty()) return 0;
 
     int column = 0;
-    const auto &tokens = line.Tokens();
-    const auto &front = tokens.front();
+    const auto &front = line.Tokens().front();
 
     if (front.before.action != verible::SpacingDecision::kPreserve) {
       column += line.IndentationSpaces();
@@ -763,33 +793,10 @@
     }
     column += front.token->text().length();
 
+    const auto &tokens = line.Tokens();
     for (size_t i = 1; i < tokens.size(); ++i) {
       const auto &ftoken = tokens[i];
-      switch (ftoken.before.action) {
-        case verible::SpacingDecision::kPreserve: {
-          if (ftoken.before.preserved_space_start !=
-              verible::string_view_null_iterator()) {
-            const std::string_view leading = ftoken.OriginalLeadingSpaces();
-            const auto last_nl = leading.find_last_of('\n');
-            if (last_nl == std::string_view::npos) {
-              column += leading.length();
-            } else {
-              column = static_cast<int>(leading.length() - last_nl - 1);
-            }
-          } else {
-            column += ftoken.before.spaces;
-          }
-          break;
-        }
-        case verible::SpacingDecision::kWrap:
-          // Newline then only the wrap indent (same as FormattedToken emit).
-          column = ftoken.before.spaces;
-          break;
-        case verible::SpacingDecision::kAlign:
-        case verible::SpacingDecision::kAppend:
-          column += ftoken.before.spaces;
-          break;
-      }
+      AdjustColumnUsingTokenSpacing(ftoken, &column);
       // Do not add the last token's length: that is the EOL comment whose
       // starting column we want.
       if (i + 1 < tokens.size()) {