A `#` preceded by whitespace and outside quotes now ends the value, so
`TR_DEBUG_DRAW=0 # hides the grid` resolves to `0` instead of the
whole tail. Values that are still not plain tokens (whitespace, `#`, an
unclosed quote) get one `[dotenv] WARNING` line naming file, key, raw value
and the fact that the reader falls back to its DEFAULT, instead of being
applied silently. Guard test 29 -> 47 checks.
SirStone