[clang] [clang-format] Add option AllowShortRecordsOnASingleLine (PR #154580)

[Björn Schäpers via cfe-commits]

================
@@ -453,6 +453,19 @@ class LineJoiner {
       }
     }
 
+    auto ShouldMergeShortRecords = [this, &I, &NextLine, PreviousLine,
+                                    TheLine]() {
+      if (Style.AllowShortRecordsOnASingleLine == FormatStyle::SRS_All)
+        return true;
+      if (Style.AllowShortRecordsOnASingleLine == FormatStyle::SRS_Empty &&
+          NextLine.First->is(tok::r_brace)) {
+        return true;
+      }
+      return false;
+    };
+
+    bool MergeShortRecord = ShouldMergeShortRecords();
----------------
HazardyKnusperkeks wrote:

```suggestion
    const bool MergeShortRecord = [this, &NextLine]() {
      switch (Style.AllowShortRecordsOnASingleLine) {
        case FormatStyle::SRS_All: return true;
        case FormatStyle::SRS_Empty: return NextLine.First->is(tok::r_brace);
        case FormatStyle::SRS_Never: return false;
      }
    }();
```

https://github.com/llvm/llvm-project/pull/154580