[clang] Ignore inline namespace for `hasName` (#109147)
Add a new enumeration `SuppressInlineNamespaceMode` to `PrintingPolicy` that
is explicit about how to handle inline namespaces. `SuppressInlineNamespace`
uses that enumeration now instead of a Boolean value.
Specializing a template from an inline namespace should be transparent.
For instance
```
namespace foo {
inline namespace v1 {
template<typename A>
void function(A&);
}
}
namespace foo {
template<>
void function<int>(int&);
}
```
`hasName` should match both declarations of `foo::function`.
Makes the behavior of `matchesNodeFullSlow` and `matchesNodeFullFast`
consistent, fixing an assert inside `HasNameMatcher::matchesNode`.
