Added <!-- %revision% --> place-holder

Author: ishaid

src/wireviz/templates/README.md

@@ -40,6 +40,7 @@ Note that there must be one single space between `--` and `%` at both ends.
 | `<!-- %sheet_total% -->`   | `1` (multi-page documents not yet supported) |
 | `<!-- %diagram% -->`       | Embedded SVG diagram as valid HTML |
 | `<!-- %diagram_png_b64% -->` | Embedded base64 encoded PNG diagram as URI |
+| `<!-- %revision% -->`        | The name of the last revision |
 | `<!-- %{item}% -->`             | String or numeric value of `metadata.{item}` |
 | `<!-- %{item}_{i}% -->`         | Category number `{i}` within dict value of `metadata.{item}` |
 | `<!-- %{item}_{i}_{key}% -->`   | Value of `metadata.{item}.{category}.{key}` |

src/wireviz/wv_output.py

@@ -64,6 +64,13 @@ def get_mime_subtype(filename: Union[str, Path]) -> str:
     return mime_subtype
 
 
+def _get_latest_revision(metadata: Dict) -> str:
+    if not "revisions" in metadata:
+        return ""
+    revision = list(metadata.get("revisions"))[-1]
+    return revision
+
+
 def embed_svg_images_file(
     filename_in: Union[str, Path], overwrite: bool = True
 ) -> None:
@@ -148,6 +155,7 @@ def svgdata() -> str:
         "<!-- %template_sheetsize% -->": metadata.get("template", {}).get(
             "sheetsize", ""
         ),
+        "<!-- %revision% -->": _get_latest_revision(metadata),
     }
 
     def replacement_if_used(key: str, func: Callable[[], str]) -> None: