Add exception X::Syntax::AddCategorial::MissingSeparator

lib/Type/X/Syntax/AddCategorial/MissingSeparator.pod

@@ -0,0 +1,28 @@
+=begin pod
+
+=TITLE class X::Syntax::AddCategorial::MissingSeparator
+
+=SUBTITLE Compilation error due to defining circumfix operator without 
+separator between opening and closing terminator
+
+    class X::Syntax::AddCategorial::MissingSeparator does X::Syntax { }
+
+Syntax error when a circumfix operator is defined, but within the definition
+opening and closing terminators are not separated by a whitespace.
+
+For example 
+
+    multi sub circumfix:<⌊⌋>($a) { return $a.floor; }
+
+dies with
+
+    ===SORRY!===
+    Unable to identify both starter and stopper from ⌊⌋
+    Perhaps you forgot to separate them with whitespace?
+
+Valid code would contain an extra whitespace:
+
+    multi sub circumfix:<⌊ ⌋>($a) { return $a.floor; }
+    my $n = ⌊4.9⌋;  ## $n is now 4
+
+=end pod

type-graph.txt

@@ -386,6 +386,7 @@ class X::Syntax::Regex::Adverb                     does X::Syntax
 class X::Syntax::Regex::SolitaryQuantifier         does X::Syntax
 class X::Syntax::Signature::InvocantMarker         does X::Syntax
 class X::Syntax::Term::MissingInitializer          does X::Syntax
+class X::Syntax::AddCategorial::MissingSeparator   does X::Syntax
 class X::Syntax::Extension::Category               does X::Syntax
 class X::Syntax::InfixInTermPosition               does X::Syntax
 class X::Syntax::Pod::BeginWithoutIdentifier       does X::Syntax does X::Pod