[clang-format] Align trailing comments for function parameters (#164458)

before

```C++
void foo(int   name, // name
         float name, // name
         int   name)   // name
{}
```

after

```C++
void foo(int   name, // name
         float name, // name
         int   name) // name
{}
```

Fixes #85123.

As the bug report explained, the procedure for aligning the function
parameters previously failed to update `StartOfTokenColumn`.

clang/lib/Format/WhitespaceManager.cpp

@@ -516,7 +516,8 @@ static unsigned AlignTokens(const FormatStyle &Style, F &&Matches,
   };
 
   unsigned I = StartAt;
-  for (unsigned E = Changes.size(); I != E; ++I) {
+  const auto E = Changes.size();
+  for (; I != E; ++I) {
     auto &CurrentChange = Changes[I];
     if (CurrentChange.indentAndNestingLevel() < IndentAndNestingLevel)
       break;
@@ -660,8 +661,15 @@ static unsigned AlignTokens(const FormatStyle &Style, F &&Matches,
     MatchedIndices.push_back(I);
   }
 
-  EndOfSequence = I;
+  // Pass entire lines to the function so that it can update the state of all
+  // tokens that move.
+  for (EndOfSequence = I;
+       EndOfSequence < E && Changes[EndOfSequence].NewlinesBefore == 0;
+       ++EndOfSequence) {
+  }
   AlignCurrentSequence();
+  // The return value should still be where the level ends. The rest of the line
+  // may contain stuff to be aligned within an outer level.
   return I;
 }
 

clang/unittests/Format/FormatTest.cpp

@@ -19851,6 +19851,14 @@ TEST_F(FormatTest, AlignConsecutiveDeclarations) {
                "  Test &operator=(const Test &) = default;\n"
                "};",
                Alignment);
+
+  // The comment to the right should still align right.
+  verifyFormat("void foo(int   name, // name\n"
+               "         float name, // name\n"
+               "         int   name) // name\n"
+               "{}",
+               Alignment);
+
   unsigned OldColumnLimit = Alignment.ColumnLimit;
   // We need to set ColumnLimit to zero, in order to stress nested alignments,
   // otherwise the function parameters will be re-flowed onto a single line.