[clang-format] Add BreakBeforeTemplateCloser option (#118046)

In clang-format, multiline templates have the `>` on the same line as
the last parameter:

```c++
template <
    typename Foo,
    typename Bar>
void foo() {
```

I would like to add an option to put the `>` on the next line, like
this:

```c++
template <
    typename Foo,
    typename Bar
>
void foo() {
```

An example of a large project that uses this style is NVIDIA's CUTLASS,
here is an example:


https://github.com/NVIDIA/cutlass/blob/main/include/cutlass/epilogue/dispatch_policy.hpp#L149-L156

My reasoning is that it reminds me of this style of braces:

```c++
if (foo()) {
    bar();
    baz();}
```

Most people agree this is better:

```c++
if (foo()) {
    bar();
    baz();
}
```

---------

Co-authored-by: Owen Pan <owenpiano@gmail.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
index f02bf95..387daad 100644
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -1014,6 +1014,8 @@ template <> struct MappingTraits<FormatStyle> {
     IO.mapOptional("BreakBeforeBraces", Style.BreakBeforeBraces);
     IO.mapOptional("BreakBeforeInlineASMColon",
                    Style.BreakBeforeInlineASMColon);
+    IO.mapOptional("BreakBeforeTemplateCloser",
+                   Style.BreakBeforeTemplateCloser);
     IO.mapOptional("BreakBeforeTernaryOperators",
                    Style.BreakBeforeTernaryOperators);
     IO.mapOptional("BreakBinaryOperations", Style.BreakBinaryOperations);
@@ -1535,6 +1537,7 @@ FormatStyle getLLVMStyle(FormatStyle::LanguageKind Language) {
   LLVMStyle.BreakBeforeBraces = FormatStyle::BS_Attach;
   LLVMStyle.BreakBeforeConceptDeclarations = FormatStyle::BBCDS_Always;
   LLVMStyle.BreakBeforeInlineASMColon = FormatStyle::BBIAS_OnlyMultiline;
+  LLVMStyle.BreakBeforeTemplateCloser = false;
   LLVMStyle.BreakBeforeTernaryOperators = true;
   LLVMStyle.BreakBinaryOperations = FormatStyle::BBO_Never;
   LLVMStyle.BreakConstructorInitializers = FormatStyle::BCIS_BeforeColon;