[clang] clang-format: Add "AllowShortNamespacesOnASingleLine" option (PR #105597)

[Owen Pan via cfe-commits]

================
@@ -616,6 +626,62 @@ class LineJoiner {
     return 1;
   }
 
+  unsigned tryMergeNamespace(SmallVectorImpl<AnnotatedLine *>::const_iterator I,
+                             SmallVectorImpl<AnnotatedLine *>::const_iterator E,
+                             unsigned Limit) {
+    if (Limit == 0)
----------------
owenca wrote:

```suggestion
                             int Limit) {
    if (Limit <= 0)
```
See below.

https://github.com/llvm/llvm-project/pull/105597