## Changes
While investigating #1629, I found that Go doesn't allow characters
outside the set documented at
https://pkg.go.dev/golang.org/x/mod/module#CheckFilePath.
To fix this, I changed the relevant test case to create the fixtures it
needs instead of loading it from the `testdata` directory (in
`renderer_test.go`).
Some test cases in `config_test.go` depended on templated paths without
needing to do so. In the process of fixing this, I refactored these
tests slightly to reduce dependencies between them.
This change also adds a test case to ensure that all files in the
repository are allowed to be part of a module (per the earlier
`CheckFilePath` function).
Fixes#1629.
## Tests
I manually confirmed I could import the repository as a Go module.
## Changes
The `.tmpl` extension is only meant as a qualifier for whether the file
content is executed as a template. All file paths in the `template`
directory should be treated as valid go text templates.
Before only paths with the `.tmpl` extensions would be resolved as
templates, after this change, all file paths are interpreted as
templates.
## Tests
Unit test. The newly added unit tests also asserts that the file path is
correct, even when the `.tmpl` extension is missing.