all: Format code with gofumpt

See https://github.com/mvdan/gofumpt

common/herrors/error_locator_test.go

@@ -125,5 +125,4 @@ E`, offsetMatcher)
 	c.Assert(location.Lines, qt.DeepEquals, []string{"A", "B", "C", "D"})
 	c.Assert(location.Position().LineNumber, qt.Equals, 2)
 	c.Assert(location.LinesPos, qt.Equals, 1)
-
 }

common/herrors/file_error.go

@@ -21,9 +21,7 @@ import (
 	"github.com/pkg/errors"
 )
 
-var (
-	_ causer = (*fileError)(nil)
-)
+var _ causer = (*fileError)(nil)
 
 // FileError represents an error when handling a file: Parsing a config file,
 // execute a template etc.

common/herrors/file_error_test.go

@@ -52,5 +52,4 @@ func TestToLineNumberError(t *testing.T) {
 		c.Assert(pos.ColumnNumber, qt.Equals, test.columnNumber, errMsg)
 		c.Assert(errors.Cause(got), qt.Not(qt.IsNil))
 	}
-
 }