Ruby: Add RegExpNonWordBoundary to RegExpTreeView

ruby/ql/lib/codeql/ruby/regexp/RegExpTreeView.qll

@@ -581,6 +581,15 @@ class RegExpWordBoundary extends RegExpSpecialChar {
   RegExpWordBoundary() { this.getChar() = "\\b" }
 }
 
+/**
+ * A non-word boundary, that is, a regular expression term of the form `\B`.
+ */
+class RegExpNonWordBoundary extends RegExpSpecialChar {
+  RegExpNonWordBoundary() { this.getChar() = "\\B" }
+
+  override string getAPrimaryQlClass() { result = "RegExpNonWordBoundary" }
+}
+
 /**
  * A character class escape in a regular expression.
  * That is, an escaped character that denotes multiple characters.

ruby/ql/test/library-tests/regexp/parse.expected

@@ -266,11 +266,11 @@ regexp.rb:
 #   43| [RegExpSequence] \b!a\B
 #-----| 0 -> [RegExpSpecialChar] \b
 #-----| 1 -> [RegExpConstant, RegExpNormalChar] !a
-#-----| 2 -> [RegExpSpecialChar] \B
+#-----| 2 -> [RegExpNonWordBoundary] \B
 
 #   43| [RegExpConstant, RegExpNormalChar] !a
 
-#   43| [RegExpSpecialChar] \B
+#   43| [RegExpNonWordBoundary] \B
 
 #   46| [RegExpGroup] (foo)
 #-----| 0 -> [RegExpConstant, RegExpNormalChar] foo

ruby/ql/test/library-tests/regexp/regexp.expected

@@ -108,7 +108,7 @@ term
 | regexp.rb:43:2:43:3 | \\b | RegExpSpecialChar |
 | regexp.rb:43:2:43:7 | \\b!a\\B | RegExpSequence |
 | regexp.rb:43:4:43:5 | !a | RegExpConstant,RegExpNormalChar |
-| regexp.rb:43:6:43:7 | \\B | RegExpSpecialChar |
+| regexp.rb:43:6:43:7 | \\B | RegExpNonWordBoundary |
 | regexp.rb:46:2:46:6 | (foo) | RegExpGroup |
 | regexp.rb:46:2:46:7 | (foo)* | RegExpStar |
 | regexp.rb:46:2:46:10 | (foo)*bar | RegExpSequence |