This feels like a better name since the "autocomplete engine" can, in
addition to providing autocomplete suggestions, also find declarations
of symbols and report back the symbols that are defined in a document.
Also, Cpp/ParserAutoComplete has been renamed to CppComprehensionEngine
and Shell/AutoComplete has been renamed to ShellComprehensionEngine.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
This makes them available for use by other language servers.
Also as a bonus, update the Shell language server to discover some
symbols and add go-to-definition functionality :^)