Previously, the `startSourceSpan` property could be null
but in reality it is always well defined - except for a legacy
case in the old i18n extraction/merging code, where the
typings for source-spans are already being undermined.
Making this property non-null, simplifies code elsewhere
in the project.
PR Close#38581
This commit consolidates the options that can modify the
parsing of text (e.g. HTML, Angular templates, CSS, i18n)
into an AST for further processing into a single `options`
hash.
This makes the code cleaner and more readable, but also
enables us to support further options to parsing without
triggering wide ranging changes to code that should not
be affected by these new options. Specifically, it will let
us pass information about the placement of a template
that is being parsed in its containing file, which is essential
for accurate SourceMap processing.
PR Close#28055