doc: add docs on swig-abi metapackage (#2642)

* doc: add swig abi bits

* fix: remove vscode junk

* fix: update gitignore to exclude vscode items

* style: pre-the-commit

Author: beckermr

.gitignore

@@ -54,3 +54,6 @@ yarn-error.log*
 # pyc files
 *.pyc
 __pycache__/
+
+# vscode stuff
+.vscode

docs/maintainer/knowledge_base.md

@@ -1402,13 +1402,16 @@ if you import parts of `matplotlib` that link to `libX11`.
 
 <a id="pybind11-abi-constraints"></a>
 
-### `pybind11` ABI Constraints
+<a id="pybind11-swig-abi-constraints"></a>
 
-Sometimes when different python libraries using `pybind11` interact via lower-level C++ interfaces,
-the underlying ABI between the two libraries has to match. To ease this use case, we have a `pybind11-abi`
-metapackage that can be used in the `host` section of a build. Its version is pinned globally and it has a
+### `pybind11` and `swig` ABI Constraints
+
+Sometimes when different python libraries using `pybind11`/`swig` interact via lower-level interfaces,
+the underlying ABI between the two libraries has to match. To ease this use case, we have a `pybind11-abi`/`swig-abi`
+metapackage that can be used in the `host` section of a build. Its version is pinned globally, and it has a
 run export on itself, meaning that builds with this package in `host` will have a runtime constraint on it.
-Further, the `pybind11` has a run constraint on the ABI metapackage to help ensure consistent usage.
+Further, the `pybind11`/`swig` has a run constraint on the respective ABI metapackage to help ensure
+consistent usage.
 
 To use this package in a build, put it in the host environment like so
 
@@ -1418,6 +1421,14 @@ requirements:
     - pybind11-abi
 ```
 
+or
+
+```yaml
+requirements:
+  host:
+    - swig-abi
+```
+
 <a id="knowledge-empty"></a>
 
 <a id="empty-python-packages"></a>