Fix method lookup for regexp

Fixes #1132

lang/spec.html

@@ -5858,11 +5858,11 @@ <h3>Method call expression</h3>
 library, where M is selected as follows.
 </p>
 <ul>
-<li>If the static type of <code>expression</code> is a subtype of some basic
-type with identifier B, and the module lang.B contains a function
-<code>method-name</code> then M is B. The identifier for a basic type is the
-reserved identifier used in type descriptors for subtypes of that basic type, as
-listed in the <a href="#lang_library">Lang library</a> section.</li>
+<li>If the static type of <code>expression</code> is a subtype of basic type
+with corresponding langlib module lang.B and the module lang.B contains a
+function <code>method-name</code> then M is B. The module corresponding to each
+basic type is listed in the <a href="#lang_library_modules">Lang library
+modules</a> section.</li>
 <li>Otherwise, M is <code>value</code>.</li>
 </ul>
 <p>
@@ -11217,7 +11217,7 @@ <h3 id="built-in_subtypes">Built-in subtypes</h3>
 </section>
 
 <section>
-<h3>Lang library modules</h3>
+<h3 id="lang_library_modules">Lang library modules</h3>
 <p>
 The lang library consists of the following modules. With the exception of the
 <code>lang.value</code>, <code>lang.transaction</code> and
@@ -11317,8 +11317,8 @@ <h4 id="lang.object"><code>lang.object</code> module</h4>
 <section>
 <h4 id="lang.regexp"><code>lang.regexp</code> module</h4>
 
-<p>The <code>lang.regexp</code> module corresponds to tagged data type with tag
-<code>re</code>.</p>
+<p>The <code>lang.regexp</code> module corresponds to the basic type for the
+tagged data type with tag <code>re</code>.</p>
 
 <p class="langlib"><a href="./lib/regexp.bal" type="text/plain">regexp.bal</a></p>