url: return valid file: urls fom url.format()
Checklist
-
make -j4 test
(UNIX) orvcbuild test nosign
(Windows) passes -
a test and/or benchmark is included -
the commit message follows commit guidelines
Affected core subsystem(s)
url
Description of change
file:
URLs that do not start with file://
are invalid. Browsers convert file:/etc/passwd
to file:///etc/passwd
. This is also what the docs indicate we are doing, but we're not.
Labeling semver-major
because tests have to be updated for it.