fix some typos in UCX 2.1 documentation

update general web documentation structure

add header and footer to list of build dependencies

add missing docs for cxEmptyMap

fix wrong docs for cx_stream_copy()

add missing docs for cx_invoke_destructor()

update Doxyfile to Doxygen 1.9.6

fix const-ness of non-mutating iterator creation for maps

simplify map class structure

fix inconsistent destructor requirements for list and map classes

(0) -300 -100 -10 +10 +100 tip

mercurial