docs: re-export the button/select limit constants the README advertises

README lists BUTTON_ROW_MAX/BUTTON_LABEL_MAX/SELECT_OPTION_LABEL_MAX/SELECT_PLACEHOLDER_MAX/
SELECT_MAX_OPTIONS as flat module constants, but __init__ re-exported only the message/embed
limits, so dc.BUTTON_ROW_MAX was an AttributeError - re-export all five to match the doc.

Signed-off-by: disqualifier <dev@disqualifier.me>

src/dpy_commons/__init__.py

@@ -8,6 +8,8 @@ from importlib.metadata import PackageNotFoundError, version
 
 from .embeds import fit_embed, sanitize_embed, split_embeds
 from .limits import (
+    BUTTON_LABEL_MAX,
+    BUTTON_ROW_MAX,
     EMBED_AUTHOR,
     EMBED_DESC,
     EMBED_FIELD_NAME,
@@ -18,6 +20,9 @@ from .limits import (
     EMBED_TOTAL,
     MSG_LIMIT,
     MSG_MAX_EMBEDS,
+    SELECT_MAX_OPTIONS,
+    SELECT_OPTION_LABEL_MAX,
+    SELECT_PLACEHOLDER_MAX,
 )
 from .parsing import extract_message_links, parse_message, sanitize_mentions
 from .prompts import choose, confirm
@@ -62,5 +67,10 @@ __all__ = [
     "EMBED_TOTAL",
     "EMBED_MAX_FIELDS",
     "MSG_MAX_EMBEDS",
+    "BUTTON_ROW_MAX",
+    "BUTTON_LABEL_MAX",
+    "SELECT_OPTION_LABEL_MAX",
+    "SELECT_PLACEHOLDER_MAX",
+    "SELECT_MAX_OPTIONS",
     "__version__",
 ]