Fix documentation build warnings

[cgay]

Building the docs there are many warnings that should be fixed. Some examples are below but there are a lot more if you build all docs as is done in the opendylan.org nightly update script.

opendylan/documentation/building-with-duim/source/improve.rst:: WARNING: unusable reference target found: design.html#creating-the-basic-sheet-hierarchy
opendylan/documentation/building-with-duim/source/improve.rst:: WARNING: unusable reference target found: design.html#creating-the-basic-sheet-hierarchy
opendylan/documentation/building-with-duim/source/improve.rst:: WARNING: unusable reference target found: source.html#a-task-list-manager-using-command-tables

opendylan/documentation/intro-dylan/source/why-dylan.rst:20: WARNING: term not in glossary: static
opendylan/documentation/intro-dylan/source/why-dylan.rst:25: WARNING: term not in glossary: dynamic
opendylan/documentation/intro-dylan/source/why-dylan.rst:43: WARNING: term not in glossary: functional