Update 'filename' option description in configuration

Clarified the usage of the 'filename' option in the configuration.

Author: LandonTClipp

docs/configuration.md

@@ -122,7 +122,7 @@ Parameter Descriptions
 | `dir`                                                  | :fontawesome-solid-check: | `#!yaml "{{.InterfaceDir}}"`  | The directory where the mock file will be outputted to.                                                                                                                                                                                              |
 | `exclude-subpkg-regex`                                 | :fontawesome-solid-x:     | `#!yaml []`                           | A list of regular expressions that denote which subpackages should be excluded when `#!yaml recursive: true` |
 | `exclude-interface-regex`                              | :fontawesome-solid-x:     | `#!yaml ""`                           | When set along with `include-interface-regex`, then interfaces which match `include-interface-regex` but also match `exclude-interface-regex` will not be generated. If `all` is set, or if `include-interface-regex` is not set, then `exclude-interface-regex` has no effect.                        |
-| `filename`                                             | :fontawesome-solid-check: | `#!yaml "mocks_test.go"` | The name of the file the mock will reside in.                                                                                                                                                                                                        |
+| `filename`                                             | :fontawesome-solid-check: | `#!yaml "mocks_test.go"` | The name of the file the mock will reside in. Multiple interfaces from the same source package can be placed into the same output file.                                                                                                                             |
 | `force-file-write`                                     | :fontawesome-solid-x:     | `#!yaml true`                        | When set to `#!yaml force-file-write: true`, mockery will forcibly overwrite any existing files. Otherwise, it will fail if the output file already exists. |
 | `formatter`                                            | :fontawesome-solid-x:     | `#!yaml "goimports"`                  | The formatter to use on the rendered template. Choices are: `gofmt`, `goimports`, `noop`.                                                                                                                                                            |
 | `generate`                                             | :fontawesome-solid-x:     | `#!yaml true`                         | Can be used to selectively enable/disable generation of specific interfaces. See [the related docs](generate-directive.md) for more details. |