Quote the compiler's own words for the index rule, and pin the Emacs keys

The paraphrase of why a wide index is refused was shorter and said less than
the message; and the keybinding table came from NEXT.md, which is two keys
behind flan-mode.el, so it now reads the keymap instead.

web/examples/quotes.sh

@@ -11,14 +11,16 @@ FLAN=${FLAN:-$root/_build/default/bin/main.exe}
 page=$here/../index.html
 fail=0
 
-# Look for a literal string in the page, allowing for HTML escaping of < and >.
+# The page is compared with its whitespace collapsed, so that a long compiler
+# message may be wrapped in the HTML and still be recognised as the same text.
+flat=$(sed -e 's/&lt;/</g' -e 's/&gt;/>/g' -e 's/&amp;/\&/g' "$page" | tr '\n' ' ' | tr -s ' ')
+
 want() {
-  esc=$(printf '%s' "$2" | sed -e 's/&/\&amp;/g' -e 's/</\&lt;/g' -e 's/>/\&gt;/g')
-  if grep -qF -- "$esc" "$page"; then echo "ok    $1"; else
-    echo "FAIL  $1"
-    echo "      not on the page: $2"
-    fail=1
-  fi
+  needle=$(printf '%s' "$2" | tr '\n' ' ' | tr -s ' ')
+  case $flat in
+    *"$needle"*) echo "ok    $1" ;;
+    *) echo "FAIL  $1"; echo "      not on the page: $2"; fail=1 ;;
+  esac
 }
 
 # The usage text, from the binary itself.
@@ -27,7 +29,8 @@ want "flan usage" "$("$FLAN" 2>&1 | sed -n 2p)"
 # calc-me, the first acceptance program, still answers what the page says.
 want "calc-me" "$("$FLAN" run "$root/calc-me.flan" '1 + 2 * (3 - 0.5) / 2')"
 
-# The refusal messages quoted in "Not implemented yet" and under defer.
+# The refusal and diagnostic messages quoted in the prose and in the
+# "Not implemented yet" table.
 for pair in \
   'vec:(defvar xs (Vec i32))' \
   'map:(defvar m (Map string i32))' \
@@ -35,12 +38,13 @@ for pair in \
   'handle:(defvar h (Handle i32))' \
   'fnty:(defn f [g (Fn [i32] i32)] i32 (g 1))' \
   'quoted:(defn f [] i32 (quote a))' \
-  'deferblock:(defn f [] i32 (let [x 1] (defer (print-line "a")) x))'
+  'deferblock:(defn f [] i32 (let [x 1] (defer (print-line "a")) x))' \
+  'i64index:(defconst xs [3 i32] [1 2 3]) (defn main [] i32 (let [i (i64 1)] (at xs i)))'
 do
   name=${pair%%:*}; src=${pair#*:}
   printf '%s\n' "$src" > "$here/.q.flan"
   msg=$("$FLAN" check "$here/.q.flan" 2>&1 | sed 's/^[^ ]*: //')
-  want "refusal: $name" "$msg"
+  want "message: $name" "$msg"
 done
 rm -f "$here/.q.flan"
 
@@ -59,4 +63,11 @@ want "agent declare"  "$(grep -F 'flan_agent_poll' "$root/vendor/agent/agent.fla
 want "conditions.org" "$(grep -F 'Innermost frame offering the name wins' "$root/conditions.org")"
 want "renderer"       "$(grep -F ':r 17 :g 34 :b 51 :a 68' "$root/NEXT.md")"
 
+# The Emacs bindings, from the keymap rather than from any prose about it.
+for k in "C-c C-c" "C-c C-k" "C-x C-e" "C-c C-b" "C-c C-v" "C-c C-x"; do
+  grep -qF "(kbd \"$k\")" "$root/emacs/flan-mode.el" || {
+    echo "FAIL  keybinding $k is not in flan-mode.el"; fail=1; continue; }
+  want "keybinding $k" "<kbd>$k</kbd>"
+done
+
 exit $fail

web/index.html

@@ -372,8 +372,11 @@ and logical on an unsigned one.</p>
 <p>An index converts from a narrower integer and never from a wider one. A
 <code>u32</code> index is fine — anything above 2<sup>31</sup> truncates to a negative
 <code>i32</code> and the unsigned bounds check rejects it. An <code>i64</code> index is
-refused, because 2<sup>32</sup>+5 truncates to 5 and would read the wrong element with
-no trap at all.</p>
+refused, and the message is worth reading because it is the shape of most of them:</p>
+
+<pre><code class="sh">an index is an i32, and i64 is wider — write (i32 …), because a value that does
+not fit truncates to one that does and would read the wrong element without
+tripping the bounds check</code></pre>
 
 <h2 id="structs">Structs and enums</h2>