Docs: update igir internals (#906)

docs/internals.md

@@ -11,13 +11,17 @@ Information about the inner workings of `igir`.
    - Detect headers in those files, if applicable (see [header docs](roms/headers.md))
 3. Scan each patch input path for every file (`--patch <path>`) (see [patching docs](roms/patching.md))
 4. Then for each DAT:
-   - ROMs in the DAT are filtered to only those desired (see [filtering & preference docs](roms/filtering-preferences.md))
+   - Parent/clone information is inferred if the DAT has none (see [DATs docs](./dats/overview.md))
+   - Parent/clone ROMs sets are merged or split (`--merge-roms <type>`) (see [arcade docs](./usage/arcade.md))
+   - ROMs in the DAT are filtered to only those desired (`--filter-*` options) (see [filtering & preference docs](roms/filtering-preferences.md))
    - Input files are matched to ROMs in the DAT
-   - Patch files are matched to ROMs in the DAT
+   - Patch files are matched to ROMs found
    - ROM preferences are applied (`--single`, see [filtering & preference docs](roms/filtering-preferences.md))
+   - ROMs are combined (`--zip-dat-name`)
    - ROMs are written to the output directory, if specified (`copy`, `move`, `symlink`)
      - Written ROMs are tested for accuracy, if specified (`test`)
-   - A "fixdat" is created, if specified (`fixdat`)
+   - A "dir2dat" DAT is created, if specified (`dir2dat`) (see [dir2dat docs](./dats/dir2dat.md))
+   - A "fixdat" is created, if specified (`fixdat`) (see [fixdats docs](./dats/fixdats.md))
 5. "Moved" input ROMs are deleted (`move`)
 6. Unknown files are recycled from the output directory, if specified (`clean`, see [cleaning docs](output/cleaning.md))
 7. An output report is written to the output directory, if specified (`report`, see [reporting docs](output/reporting.md))