Columns Selection DSL `nameEquals("")`

we have `nameStartsWith("")`/`nameEndsWith("")` and `nameContains("")` but not a way to check if the name exactly matches something, aside from `cols { it.name == "xx" }`, which doesn't work with the compiler plugin.

Just try to catch `"foo"` and not `"foobarfoo"` :P

maybe we should have `nameIs("")`, `namedExactly("")` (we cannot used `named("")`, we already have that)

Start by finding the existing nameStartsWith(""), nameEndsWith(""), and nameContains("") column-selection DSL entry points and their compiler-plugin handling. Compare candidate naming with the existing named("") API, then verify that an exact selector matches "foo" but not "foobarfoo". Done means compiler-plugin-compatible exact name selection is available with an agreed name.

Written by the indexing model from the issue text.