[polly] [clang] [clang-format] Add AllowShortType and ExceptShortType options for AlwaysBreakAfterReturnType. (PR #78011)

[Owen Pan via cfe-commits]

================
@@ -922,8 +922,39 @@ struct FormatStyle {
     ///   };
     ///   int f();
     ///   int f() { return 1; }
+    ///   int LongName::
+    ///       AnotherLongName();
     /// \endcode
     RTBS_None,
+    /// Break after return type automatically.
+    /// This mode doesn't have the same inherent restriction on breaking after
+    /// short return types as ``RTBS_None`` and is solely based on
+    /// ``PenaltyReturnTypeOnItsOwnLine``.
+    /// \code
+    ///   class A {
+    ///     int f() { return 0; };
+    ///   };
+    ///   int f();
+    ///   int f() { return 1; }
+    ///   int
+    ///   LongName::AnotherLongName();
+    /// \endcode
+    RTBS_AllowShortType,
+    /// Break after return type automatically.
+    /// ``PenaltyReturnTypeOnItsOwnLine`` is taken into account.
+    /// This mode will never break after short return types, unlike
+    /// ``RTBS_None`` which will only sometimes choose not to break after short
+    /// return types.
----------------
owenca wrote:

For example:
```suggestion
    /// Same as ``Automatic`` above, except that there is no break after short
    /// return types.
```

https://github.com/llvm/llvm-project/pull/78011