Implement indexation of readonly variables + allow invalid keywords

readonly variables no longer result in a failed indexation.

When we fail matching the scope keywords + variable patterns, only the variable
name is indexed instead of throwing an error.

phpinspect-index.el

@@ -179,6 +179,12 @@ function (think \"new\" statements, return types etc.)."
 Provide STATIC if the variable was defined as static.
 
 SCOPE should be a scope token (`phpinspect-scope-p')."
+  (let (readonly)
+    (when (and (phpinspect-word-p (cadr scope))
+               (equal (cadr scope) `(:word "readonly")))
+      (setq readonly t)
+      (setcdr scope (cddr scope)))
+
     (setq scope (take 5 (seq-filter #'phpinspect-not-comment-p scope)))
     (let (variable-name type)
       (cond
@@ -195,16 +201,18 @@ SCOPE should be a scope token (`phpinspect-scope-p')."
               ;; docstring.
               type (phpinspect--variable-type-string-from-comment
                     comment-before variable-name)))
-     (t (error (format "Failed to determine variable from scope %s" scope))))
+       (t
+        (setq variable-name (cadr (seq-find #'phpinspect-variable-p scope)))))
 
       (phpinspect--log "calling resolver from index-variable-from-scope")
       (phpinspect--make-variable
        ;; Static class variables are always prefixed with dollar signs when
        ;; referenced.
+       :readonly readonly
        :name (if static (concat "$" variable-name) variable-name)
        :scope `(,(car scope))
        :lifetime (when static '(:static))
-     :type (if type (funcall type-resolver (phpinspect--make-type :name type))))))
+       :type (if type (funcall type-resolver (phpinspect--make-type :name type)))))))
 
 (defun phpinspect-doc-block-p (token)
   (phpinspect-token-type-p token :doc-block))