Work around Sphinx bug with :orphan: directive
Update tabcomplete.jl to include Unicode names

The script will now download UnicodeData.txt from the Unicode Consortium website. This file is added to .gitignore.
Regenerate unicode-input-table.rst with Unicode names
Doc: "Interacting with Julia" cross-references "Unicode input"
Doc: warn about potential font rendering problems
Merge pull request #8579 from JuliaLang/cjh/moar-unicode-doc

Further improvements to Unicode documentation