Readability of warning message

A warning like:
```
warning: source examples is not a readable file or directory... skipping.
```
is hard to understand, would be better to have:
```
warning: source 'examples' is not a readable file or directory... skipping.
```

1 files changed, 2 insertions, 2 deletions

diff --git a/src/doxygen.cpp b/src/doxygen.cpp
index d551292..b218d38 100644
--- a/src/doxygen.cpp
+++ b/src/doxygen.cpp
@@ -9473,7 +9473,7 @@ static int readDir(QFileInfo *fi,
         {
           if (errorIfNotExist)
           {
-            warn_uncond("source %s is not a readable file or directory... skipping.\n",cfi->absFilePath().data());
+            warn_uncond("source '%s' is not a readable file or directory... skipping.\n",cfi->absFilePath().data());
           }
         }
         else if (cfi->isFile() &&
@@ -9553,7 +9553,7 @@ int readFileOrDirectory(const char *s,
       {
         if (errorIfNotExist)
         {
-          warn_uncond("source %s is not a readable file or directory... skipping.\n",s);
+          warn_uncond("source '%s' is not a readable file or directory... skipping.\n",s);
         }
       }
       else if (!Config_getBool(EXCLUDE_SYMLINKS) || !fi.isSymLink())