Tera error handling

[naturallymitchell]

Tera can do so much more

all we have now is "Failed to render template [name]."

[naturallymitchell]

https://docs.rs/tera/1.0.0-alpha.2/tera/struct.Error.html#methods

[Keats]

Just noticed that following along from the panic report, do not use an alpha version yet except if you like to fix breaking changes :) Things will be more stable once a beta version is released and I would take feedback on the errors reporting as it is still a bit WIP right now.

[naturallymitchell]

can't you tell @Keats I love your alpha code 💃 💃

[naturallymitchell]

we now have Lua tracebacks with tera 1.x, but I still think we can get additional errors, like failed to parse at X line and others..

[naturallymitchell]

foundpatterns/tera@0cb3d04