changing doc format and HTML literals

site/doc/pages/split_utf8.txt

@@ -7,18 +7,22 @@ str : string to be split
 compound_characters : optional, if true tries to combine compound characters
 return value : a list of Unicode characters
 
-:desc
-Splits the string 'str' into its constituent Unicode code points.
-
-If 'compound_characters' is true, split_utf8 will attempt to combine compound characters based on very simple rules:
-<li>combine characters if they're connected by a Zero-Width Joiner (ZWJ) character</li>
-<li>combine two characters if they're both a Regional Indicator Symbol Letter</li>
-<li>if a character is a Variation Selector, append it to the previous character</li>
-<li>in all other cases, characters remain on their own</li>
-
 :see
 >string
 
-:related
-**PHP:** `preg_split(//u, ...)`, `mb_*` helpers, or grapheme-aware libraries
-**JavaScript / Node.js:** `Array.from(str)` or iterator-based Unicode-aware splitting
+:content
+Splits `str` into its constituent Unicode code points.
+
+If `compound_characters` is `true`, `split_utf8()` also applies a small amount of grouping so some multi-code-point glyphs stay together. The current rules are:
+
+- combine characters joined by a Zero-Width Joiner (ZWJ)
+- combine two Regional Indicator Symbol Letter characters
+- append Variation Selectors to the previous character
+- otherwise leave characters as separate entries
+
+This is useful when simple byte-wise or ASCII splitting would break Unicode text incorrectly.
+
+Related:
+
+- PHP: `preg_split(//u, ...)`, `mb_*` helpers, or grapheme-aware libraries
+- JavaScript / Node.js: `Array.from(str)` or iterator-based Unicode-aware splitting