swift-inspect: Explicitly reference String.init(cString:)

This was briefly failing to build because of an ambiguous initializer
while making other changes, it's better to be explicit with method names
anyway.

rdar://127548384

Author: porglezomp

tools/swift-inspect/Sources/swift-inspect/RemoteMirror+Extensions.swift

@@ -97,7 +97,7 @@ extension SwiftReflectionContextRef {
   }
 
   internal func name(allocation tag: swift_metadata_allocation_tag_t) -> String?  {
-    return swift_reflection_metadataAllocationTagName(self, tag).map(String.init)
+    return swift_reflection_metadataAllocationTagName(self, tag).map(String.init(cString:))
   }
 
   internal func isContiguousArray(_ array: swift_reflection_ptr_t) -> Bool {