[clang-tools-extra] [doc] Add documentation for clang-change-namespace (PR #148277)

[Eric Li via cfe-commits]

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@@ -0,0 +1,155 @@
+======================
+Clang-Change-Namespace
+======================
+
+.. contents::
+
+.. toctree::
+  :maxdepth: 1
+
+:program:`clang-change-namespace` can be used to change the surrounding
+namespaces of class/function definitions.
+
+Classes/functions in the moved namespace will have new namespaces while
+references to symbols (e.g. types, functions) which are not defined in the
+changed namespace will be correctly qualified by prepending namespace specifiers
+before them. This will try to add shortest namespace specifiers possible.
+
+When a symbol reference needs to be fully-qualified, this adds a `::` prefix to
+the namespace specifiers unless the new namespace is the global namespace. For
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tJener wrote:

Ah, I suspect you may be looking for an Eric Liu who appears to have written the majority of the tool, which is not me. Which is to say that my lack of familiarity with this tool shouldn't really mean much.

https://github.com/llvm/llvm-project/pull/148277