gosrc.xml : use a more generic regexpr to match file/line numbers

This way liteide can also find the correct file when using testing libraries such as [github.com/stretchr/testify](https://github.com/stretchr/testify).
For example it was not previously possible to open myfile_test.go with the folowing log in the console :

```
=== RUN TestAssertLib
--- FAIL: TestAssertLib (0.00 seconds)
	assertions.go:156:

	Location:	myfile_test.go:348

	Error:		test failure

FAIL
exit status 1
```