Added inspection for unresolved symbols, macros and labels.

src/main/resources/META-INF/plugin.xml

@@ -61,6 +61,9 @@
         <localInspection implementationClass="de.platon42.intellij.plugins.m68k.inspections.M68kUnexpectedConditionalInstructionInspection"
                          displayName="Unaffected condition codes before conditional instruction" groupName="M68k"
                          enabledByDefault="true" level="WARNING"/>
+        <localInspection implementationClass="de.platon42.intellij.plugins.m68k.inspections.M68kUnresolvedReferenceInspection"
+                         displayName="Unresolved label/symbol/macro reference" groupName="M68k"
+                         enabledByDefault="true" level="WARNING"/>
     </extensions>
 
     <actions>

src/main/resources/inspectionDescriptions/M68kUnresolvedReference.html

@@ -0,0 +1,8 @@
+<html>
+<body>
+Checks if references to symbols, macros, global and local labels are resolvable.
+<!-- tooltip end -->
+<p>Currently, issues a weak warning for global labels or symbols as those
+    can be defined via macros, which are not evaluated right now</p>
+</body>
+</html>