Fix checkdoc warnings

* op-export.el (op/rearrange-category-sorted):
* org-page.el (op/do-publication):
(op/verify-configuration): Fix straight ' quote usage.
* op-template.el (op/get-category-name): Ensure that the first line is
a single, short sentence.  Quote the variable.

op-export.el

@@ -269,7 +269,7 @@ If COMPONENT-TABLE is nil, the publication will be skipped."
   "Rearrange and sort attribute property lists from FILE-ATTR-LIST. Rearrange
 according to category, and sort according to :sort-by property defined in
 `op/category-config-alist', if category is not in `op/category-config-alist',
-the default 'blog' category will be used. For sorting, later lies headmost."
+the default `blog' category will be used. For sorting, later lies headmost."
   (let (cat-alist cat-list)
     (mapc
      #'(lambda (plist)

op-template.el

@@ -64,7 +64,8 @@ BODY and push the result into cache and return it."
        (op/update-cache-item ,key (funcall (lambda () ,@body)))))
 
 (defun op/get-category-name (category)
-  "Return the name of the CATEGORY based on op/category-config-alist :label property. 
+  "Return the name of CATEGORY.
+Use :label property in `op/category-config-alist'.
 Default to capitalized CATEGORY name if no :label property found."
   (let* ((config (cdr (or (assoc category op/category-config-alist)
                           (assoc "blog" op/category-config-alist)))))

org-page.el

@@ -60,7 +60,7 @@
   "The main entrance of org-page. The entire procedure is:
 1) verify configuration
 2) read changed files on branch `op/repository-org-branch' of repository
-`op/repository-directory', the definition of 'changed files' is:
+`op/repository-directory', the definition of \"changed files\" is:
    1. if FORCE-ALL is non-nil, then all files will be published
    2. if FORCE-ALL is nil, the changed files will be obtained based on
 BASE-GIT-COMMIT
@@ -163,15 +163,15 @@ perfectly manipulated by org-page."
 `op/site-domain': <required>
 `op/personal-disqus-shortname': <optional>
 `op/personal-duoshuo-shortname': <optional>
-`op/export-backend': [optional](default 'html)
+`op/export-backend': [optional](default \\='html)
 `op/repository-org-branch': [optional] (but customization recommended)
 `op/repository-html-branch': [optional] (but customization recommended)
 `op/site-main-title': [optional] (but customization recommanded)
 `op/site-sub-title': [optional] (but customization recommanded)
 `op/personal-github-link': [optional] (but customization recommended)
 `op/personal-google-analytics-id': [optional] (but customization recommended)
 `op/theme': [optional]
-`op/highlight-render': [optional](default 'js)"
+`op/highlight-render': [optional](default \\='js)"
   (unless (and op/repository-directory
                (file-directory-p op/repository-directory))
     (error "Directory `%s' is not properly configured."