Add source path to TemplateSyntaxError

[astery]

Improves the error's visibility by adding a path to a source.

before:

== Compilation error in file lib/app_web/views/page_view.ex ==
** (Slime.TemplateSyntaxError) Unexpected indent
INPUT, Line 2, Column 0
  .panel-heading

after:

== Compilation error in file lib/app_web/views/page_view.ex ==
** (Slime.TemplateSyntaxError) Unexpected indent
lib/app_web/templates/page/_comments.html.slim, Line 2, Column 0
  .panel-heading

[doomspork]

Thank you and welcome @astery! If you have any additional changes, please do open PRs, would love to get some other folks involved in the project.

[doomspork]

I will update CI today/tomorrow so this passes 👍

[astery]

Thank you! I assume ci is failing because it expects a string as otp version instead of an integer, but I'm not sure didn't check that.