i18n: use saved object to get actual function information if available To list up available compression types instead of ".. bundlecompressionmarker" in "hg help bundlespec" output, proxy object "docobject" is used, because: - current online help system requires that __doc__ of registered object (maybe, function) is already well formatted in reST syntax - bundletype() method of compressionengine classes is used to list up available compression types, but - __doc__ of bundletype() object (= "instancemethod") is read-only On the other hand, hggettext requires original function object, in order to get document location in source code. Therefore, description of each compression types isn't yet translatable. Even if translatable, translators should make much effort to determine location of original texts in source code. To get actual function information, this patch makes hggettext use function object saved as "_origfunc", if it is available. This patch also changes bundlecompressiontopics() side, in order to explain how these changes work easily. This patch is a part of preparations for making description of each compression types translatable.