capital_letter was never used

R=rsc
DELTA=2  (0 added, 1 deleted, 1 changed)
OCL=31472
CL=31477

doc/go_spec.html

@@ -101,7 +101,6 @@ The following terms are used to denote specific Unicode character classes:
 <pre class="ebnf">
 unicode_char   = /* an arbitrary Unicode code point */ .
 unicode_letter = /* a Unicode code point classified as "Letter" */ .
-capital_letter = /* a Unicode code point classified as "Letter, uppercase" */ .
 unicode_digit  = /* a Unicode code point classified as "Digit" */ .
 </pre>
 
@@ -1329,7 +1328,7 @@ Some identifiers are <i>exported</i> and can be referenced using
 If an identifier satisfies these two conditions:
 </p>
 <ol>
-<li>the first character of the identifier's name is a Unicode upper case letter;
+<li>the first character of the identifier's name is a Unicode upper case letter (Unicode class "Lu");
 <li>the identifier is declared at the package level or is a field or method of a type
 declared at the top level;
 </ol>