more docs

docs/api-reference/dtypes.md

@@ -0,0 +1,22 @@
+# `narwhals.dtypes`
+
+::: narwhals.dtypes
+    handler: python
+    options:
+      members:
+        - Int64
+        - Int32
+        - Int16
+        - Int8
+        - UInt64
+        - UInt32
+        - UInt16
+        - UInt8
+        - Float64
+        - Float32
+        - Boolean
+        - String
+        - Datetime
+      show_root_heading: false
+      show_source: false
+      show_bases: false

docs/api-reference/expressions.md

@@ -23,6 +23,5 @@
         - std
         - str
         - sum
-      show_root_heading: false
       show_source: false
       show_bases: false

docs/why.md

@@ -12,7 +12,8 @@ print(3 in pd.Series([1, 2, 3]))
 print(3 in pl.Series([1, 2, 3]))
 ```
 
-Try it out and see ;)
+Try it out and see ;) Spoiler alert: they don't. pandas checks if `3` is in the index,
+Polars checks if it's in the values.
 
 How about
 ```python
@@ -30,9 +31,10 @@ df_left.join(df_right, left_on='b', right_on='c', how='left')
 
 ?
 
-There are several such subtle difference between the libraries. By having a unified,
-simple, and predictable API, you can focus on behaviour rather than on slight implementation differences.
+There are several such subtle difference between the libraries. Writing dataframe-agnostic code is hard!
+But by having a unified, simple, and predictable API, you can focus on behaviour rather than on subtle
+implementation differences.
 
-Furthermore, both pandas and Polars frequently deprecate behaviour. By having a simple, predictable, and
-mostly stable API, which is tested nightly against the most recent commits from both pandas and Polars,
-you can develop with a lot more confidence.
+Furthermore, both pandas and Polars frequently deprecate behaviour. Narwhals handles this for you by
+testing against nightly builds of both libraries and handling backwards compatibility internally 
+(so you don't have to!).

mkdocs.yml

@@ -18,7 +18,11 @@ nav:
     - api-reference/dataframe.md
     - api-reference/lazyframe.md
     - api-reference/series.md
+    - api-reference/series_str.md
     - api-reference/expressions.md
+    - api-reference/expressions_str.md
+    - api-reference/expressions_dt.md
+    - api-reference/dtypes.md
 theme:
   name: material
   font: false