docs: add the docs for loc and iloc indexers (#446)

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Fixes #<issue_number_goes_here> 🦕

Author: ashleyxuu

docs/reference/bigframes.pandas/index.rst

@@ -9,6 +9,7 @@ BigQuery DataFrames (pandas)
     general_functions
     series
     frame
+    indexers
     indexing
     window
     groupby

docs/reference/bigframes.pandas/indexers.rst

@@ -0,0 +1,32 @@
+
+=========
+Indexers
+=========
+
+ILocDataFrameIndexer
+--------------------
+.. autoclass:: bigframes.core.indexers.ILocDataFrameIndexer
+    :members:
+    :inherited-members:
+    :undoc-members:
+
+IlocSeriesIndexer
+-----------------
+.. autoclass:: bigframes.core.indexers.IlocSeriesIndexer
+    :members:
+    :inherited-members:
+    :undoc-members:
+
+LocDataFrameIndexer
+-------------------
+.. autoclass:: bigframes.core.indexers.LocDataFrameIndexer
+    :members:
+    :inherited-members:
+    :undoc-members:
+
+LocSeriesIndexer
+----------------
+.. autoclass:: bigframes.core.indexers.LocSeriesIndexer
+    :members:
+    :inherited-members:
+    :undoc-members:

docs/templates/toc.yml

@@ -40,8 +40,16 @@
       - name: SeriesGroupBy
         uid: bigframes.core.groupby.SeriesGroupBy
       name: Groupby
-    - name: Indexes
-      uid: bigframes.core.indexes.index.Index
+    - items:
+      - name: ILocDataFrameIndexer
+        uid: bigframes.core.indexers.ILocDataFrameIndexer
+      - name: IlocSeriesIndexer
+        uid: bigframes.core.indexers.IlocSeriesIndexer
+      - name: LocDataFrameIndexer
+        uid: bigframes.core.indexers.LocDataFrameIndexer
+      - name: LocSeriesIndexer
+        uid: bigframes.core.indexers.LocSeriesIndexer
+      name: Indexers
     - name: pandas
       uid: bigframes.pandas
     - items:

third_party/bigframes_vendored/pandas/core/frame.py

@@ -5111,7 +5111,20 @@ def replace(
 
     @property
     def iloc(self):
-        """Purely integer-location based indexing for selection by position."""
+        """Purely integer-location based indexing for selection by position.
+
+        Returns:
+            bigframes.core.indexers.ILocDataFrameIndexer: Purely integer-location Indexers.
+        """
+        raise NotImplementedError(constants.ABSTRACT_METHOD_ERROR_MESSAGE)
+
+    @property
+    def loc(self):
+        """Access a group of rows and columns by label(s) or a boolean array.
+
+        Returns:
+            bigframes.core.indexers.ILocDataFrameIndexer: Indexers object.
+        """
         raise NotImplementedError(constants.ABSTRACT_METHOD_ERROR_MESSAGE)
 
     @property

third_party/bigframes_vendored/pandas/core/series.py

@@ -3313,7 +3313,20 @@ def map(
 
     @property
     def iloc(self):
-        """Purely integer-location based indexing for selection by position."""
+        """Purely integer-location based indexing for selection by position.
+
+        Returns:
+            bigframes.core.indexers.IlocSeriesIndexer: Purely integer-location Indexers.
+        """
+        raise NotImplementedError(constants.ABSTRACT_METHOD_ERROR_MESSAGE)
+
+    @property
+    def loc(self):
+        """Access a group of rows and columns by label(s) or a boolean array.
+
+        Returns:
+            bigframes.core.indexers.LocSeriesIndexer: Indexers object.
+        """
         raise NotImplementedError(constants.ABSTRACT_METHOD_ERROR_MESSAGE)
 
     @property