strings: add French "café" to the first comparison

The first cell compared "hello" (pure ASCII, 1 byte/char) with
"สวัสดี" (Thai, 3 bytes/char) but skipped the middle ground. Adding
"café" between them gives a three-row reading:

  English hello  5 code points  5 bytes  (ASCII)
  French  café   4 code points  5 bytes  (é = 2 UTF-8 bytes)
  Thai    สวัสดี 6 code points  18 bytes (each char = 3 bytes)

The example already used "café" in the third cell to demonstrate
strip/upper/encode; lifting it into the opening comparison links
the three cells around one progression of byte costs and removes
the jump from "ASCII" to "completely non-Latin" without a stepping
stone.

Both the :::program block (runnable code) and the matching :::cell
(walkthrough) updated together; the cell's expected output now
shows the three-row table; example_loader verifies the cell output
matches what the program prints.

Author: claude

src/asset_manifest.py

@@ -1,3 +1,3 @@
 # Generated by scripts/fingerprint_assets.py. Do not edit by hand.
 ASSET_PATHS = {'SITE_CSS': '/site.1452cc5609f2.css', 'SYNTAX_JS': '/syntax-highlight.3b6c7f730d46.js', 'EDITOR_JS': '/editor.dd81f5171b14.js'}
-HTML_CACHE_VERSION = '54735cba7a40'
+HTML_CACHE_VERSION = '0405776651fd'

src/example_sources/strings.md

@@ -15,9 +15,10 @@ Use `str` when you mean text, and encode to `bytes` only at boundaries such as f
 :::program
 ```python
 english = "hello"
+french = "café"
 thai = "สวัสดี"
 
-for label, word in [("English", english), ("Thai", thai)]:
+for label, word in [("English", english), ("French", french), ("Thai", thai)]:
     print(label, word, len(word), len(word.encode("utf-8")))
 
 print(thai[0])
@@ -32,18 +33,20 @@ print(clean.encode("utf-8"))
 :::
 
 :::cell
-Compare an English greeting with a Thai greeting. Both are Python `str` values, but UTF-8 uses one byte for each ASCII code point and multiple bytes for many non-ASCII code points.
+Compare three words by code-point count and UTF-8 byte count. ASCII characters take one byte each (`hello` → 5 bytes); the `é` in `café` is one code point but two UTF-8 bytes; each Thai character takes three. The `str` type abstracts over all three.
 
 ```python
 english = "hello"
+french = "café"
 thai = "สวัสดี"
 
-for label, word in [("English", english), ("Thai", thai)]:
+for label, word in [("English", english), ("French", french), ("Thai", thai)]:
     print(label, word, len(word), len(word.encode("utf-8")))
 ```
 
 ```output
 English hello 5 5
+French café 4 5
 Thai สวัสดี 6 18
 ```
 :::