bug: value completions are available after the actual value

[Druue]

Value completions are available after a value (but not immediately like one space after) -- note, this only seems to affect url completions, completions do not show up again on the same line for provider, schemas, and relationMode. This will be a logic bug in psl/schema_ast/find_at_position.rs regarding source positions

Related: XYZ_URL showing up as a completion within the text env but not between v and (

DIRECT_URL (and the other _URL completions) should only be available as a completion either between the "" if present, or between () of env()