* [ breaking ] remove parsing of dangling binders
It used to be the case that
```
ID : Type -> Type
ID a = a
test : ID (a : Type) -> a -> a
test = \ a, x => x
```
and
```
head : List $ a -> Maybe a
head [] = Nothing
head (x :: _) = Just x
```
were accepted but these are now rejected because:
* `ID (a : Type) -> a -> a` is parsed as `(ID (a : Type)) -> a -> a`
* `List $ a -> Maybe a` is parsed as `List (a -> Maybe a)`
Similarly if you want to use a lambda / rewrite / let expression as
part of the last argument of an application, the use of `$` or parens
is now mandatory.
This should hopefully allow us to make progress on #1703
Why:
* To implement robust cross-project go-to-definition in LSP
i.e you can jump to definition of any global name coming
from library dependencies, as well as from the local project files.
What it does:
* Modify `FC`s to carry `ModuleIdent` for .idr sources,
file name for .ipkg sources or nothing for interactive runs.
* Add `--install-with-src` to install the source code alongside
the ttc binaries. The source is installed into the same directory
as the corresponding ttc file. Installed sources are made read-only.
* As we install the sources pinned to the related ttc files we gain
the versioning of sources for free.
