Switch llvm-documentation to overlay convention

.orchestra/config/components.yml

 #@ load("@ytt:template", "template")
 #@ load("@ytt:data", "data")
 
-#@ load("/components/llvm_documentation.lib.yml", "llvm_documentation_component")
 #@ load("/components/llvmcpy.lib.yml", "llvmcpy_component")
 #@ load("/components/clang_release.lib.yml", "clang_release_component")
 #@ load("/components/glib.lib.yml", "glib_component")
@@ -47,7 +46,6 @@
 
 #@ load("/global_options.lib.yml", "options")
 components:
-  llvm-documentation: #@ llvm_documentation_component
   llvmcpy: #@ llvmcpy_component
   clang-release: #@ clang_release_component
   glib: #@ glib_component

.orchestra/config/components/llvm_documentation.lib.yml → .orchestra/config/components/llvm_documentation.yml

+#@ load("@ytt:overlay", "overlay")
 #@ load("/lib/make.lib.yml", "make")
 
 #@yaml/text-templated-strings
@@ -69,6 +70,8 @@ builds:
       EOF
 #@ end
 
+#@overlay/match by=overlay.all, expects=1
+#@overlay/match-child-defaults missing_ok=True
 ---
-#@ llvm_documentation_component = _llvm_documentation_component()
-
+components:
+  llvm-documentation: #@ _llvm_documentation_component()