[clang-tools-extra] [clangd] Allow "move function body out-of-line" in non-header files (PR #69704)

[kadir çetinkaya via cfe-commits]

================
@@ -19,7 +19,7 @@ TWEAK_TEST(DefineOutline);
 
 TEST_F(DefineOutlineTest, TriggersOnFunctionDecl) {
   FileName = "Test.cpp";
-  // Not available unless in a header file.
+  // Not available for free function unless in a header file.
----------------
kadircet wrote:

well, available for:
```
namespace {
struct Foo { void ba^r() {} };
}
```
and
```
namespace ns {
struct Foo { void ba^r() {} };
}
```
and
```
struct Foo { void ba^r() {} };
```

unavailable for:
```
namespace ns {
struct Foo { void bar(); };
void Foo::b^ar() {}
}
```

https://github.com/llvm/llvm-project/pull/69704