Update python_tag select to include python limited_api

This is needed after python/dist:dist's limited_api_wheels was updated from 3.7->3.8 and was causing us to mislabel the python_tag for our 3.8 limited api wheels as the system python version of 3.7.

Also:
* Add LINT to prevent next time
* Clean up some documentation
PiperOrigin-RevId: 621915013

python/dist/BUILD.bazel

@@ -333,12 +333,17 @@ py_wheel(
         "//conditions:default": "any",
     }),
     python_requires = ">=3.8",
+    # LINT.IfChange(python_tag)
     python_tag = selects.with_or({
-        "//python:full_api_3.8": "cp38",
+        ("//python:limited_api_3.8", "//python:full_api_3.8"): "cp38",
         "//python:full_api_3.9": "cp39",
         "//python:limited_api_3.10": "cp310",
         "//conditions:default": "cp" + SYSTEM_PYTHON_VERSION,
     }),
+    # LINT.ThenChange(
+    #    :full_api_version,
+    #    :limited_api_wheels,
+    # )
     strip_path_prefixes = [
         "python/dist/",
         "python/",
@@ -432,16 +437,19 @@ py_dist(
         "win64",
     ],
     # Windows needs version-specific wheels until 3.10.
+    # LINT.IfChange(full_api_version)
     full_api_versions = [
         "38",
         "39",
     ],
+    # LINT.ThenChange(:python_tag)
     # Limited API: these wheels will satisfy any Python version >= the
     # given version.
     #
     # Technically the limited API doesn't have the functions we need until
-    # 3.10, but on Linux we can get away with using 3.7 (see ../python_api.h for
+    # 3.10, but on Linux we can get away with using 3.1+ (see ../python_api.h for
     # details).
+    # LINT.IfChange(limited_api_wheels)
     limited_api_wheels = {
         "win32": "310",
         "win64": "310",
@@ -449,6 +457,7 @@ py_dist(
         "linux-aarch_64": "38",
         "osx-universal2": "38",
     },
+    # LINT.ThenChange(:python_tag)
     pure_python_wheel = ":pure_python_wheel",
     tags = ["manual"],
 )