"doc" build target is broken

[AlanGriffiths]

$ cmake --build cmake-build-release --target doc
Built target guides
/bin/sh: 1: .: cannot open .sphinx/venv/bin/activate: No such file
make[4]: *** [Makefile:36: html] Error 2
gmake[3]: *** [doc/CMakeFiles/doc.dir/build.make:70: doc/CMakeFiles/doc] Error 2
gmake[2]: *** [CMakeFiles/Makefile2:2292: doc/CMakeFiles/doc.dir/all] Error 2
gmake[1]: *** [CMakeFiles/Makefile2:2299: doc/CMakeFiles/doc.dir/rule] Error 2
gmake: *** [Makefile:270: doc] Error 2

Which affects the dependent targets "regenerate-miral-symbols-map" and "regenerate-miroil-symbols-map"

[AlanGriffiths]

This seems to have been an artefact of an old working copy. Fixed by running

make -C cmake-build-release/doc/sphinx install