Update doc

Author: JukkaL

mypyc/doc/str_operations.rst

@@ -19,8 +19,7 @@ Operators
 ---------
 
 * Concatenation (``s1 + s2``)
-* Indexing (``s[n]``)
-  * Also ``ord(s[n])``, which avoids the temporary length-1 str
+* Indexing (``s[n]``; also ``ord(s[n])``, which avoids the temporary length-1 string)
 * Slicing (``s[n:m]``, ``s[n:]``, ``s[:m]``)
 * Comparisons (``==``, ``!=``)
 * Augmented assignment (``s1 += s2``)