Make label files look more like cc65 output

The cc65 docs say VICE labels start with '.'.  Also, output local
labels prefixed with '@', per ca65 convention.  The default output
file is now "labels.lbl".

Added some minimal documentation.

(issue #151)

SourceGen/LabelFileGenerator.cs

@@ -70,7 +70,15 @@ public void Generate(StreamWriter outStream) {
             // VICE format is "add_label <address> <label>", but may be abbreviated "al".
             // We could also use ACME format ("labelname = $1234 ; Maybe a comment").
             foreach (Symbol sym in symList) {
-                outStream.WriteLine("al " + sym.Value.ToString("x6") + " " + sym.Label);
+                string label = sym.LabelWithoutTag;
+                if (sym.IsNonUnique) {
+                    // Use the cc65 convention for local labels.
+                    label = '@' + label;
+                }
+                // The cc65 docs (https://www.cc65.org/doc/debugging-4.html) say all labels
+                // must be prefaced with '.'.
+                label = '.' + label;
+                outStream.WriteLine("al " + sym.Value.ToString("x6") + " " + label);
             }
         }
     }

SourceGen/MainController.cs

@@ -2566,8 +2566,8 @@ public void GenerateLabels() {
             string filter;
             switch (dlg.Format) {
                 case LabelFileGenerator.LabelFmt.VICE:
-                    ext = ".vs";
-                    filter = "VICE commands (*.vs)|*.vs";
+                    ext = ".lbl";
+                    filter = "VICE labels (*.lbl)|*.lbl";
                     break;
                 default:
                     Debug.Assert(false, "bad format");

SourceGen/Symbol.cs

@@ -84,6 +84,7 @@ public enum LabelAnnotation {
         /// <remarks>
         /// Non-unique labels have extra stuff at the end to make them unique.  That is
         /// included here, so that the Label field is still viable as a unique identifier.
+        /// Use <see cref="LabelWithoutTag"/> to get just the label.
         /// </remarks>
         public string Label { get; private set; }
 

docs/sgmanual/codegen.html

@@ -385,7 +385,7 @@ <h2 id="export-source">Exporting Source Code</h2>
 control over which columns are included.  The HTML version is augmented
 with links and (optionally) images.</p>
 
-<p>Use File &gt; Export to open the export dialog.  You have several
+<p>Use <samp>File &gt; Export</samp> to open the export dialog.  You have several
 options:</p>
 <ul>
   <li><b>Include only selected lines</b>.  This allows you to choose between
@@ -425,6 +425,13 @@ <h2 id="export-source">Exporting Source Code</h2>
 <p>All output uses UTF-8 encoding.  Filenames of HTML files will have '#'
 replaced with '_' to make linking easier.</p>
 
+
+<h2 id="generate-labels">Generating Label Files</h2>
+<p>Some debuggers allow the import of labels associated with addresses.
+To generate such a file, use <samp>File &gt; Generate Label File</samp>.</p>
+<p>Select the desired output format (currently only VICE label commands
+are supported), and whether or not to include auto-generated labels.</p>
+
 </div>
 
 <div id="footer">

docs/sgmanual/index.html

@@ -140,6 +140,7 @@ <h2>Contents</h2>
       </ul></li>
     </ul></li>
     <li><a href="codegen.html#export-source">Exporting Source Code</a>
+    <li><a href="codegen.html#generate-labels">Generating Label Files</a>
   </ul></li>
 
   <li><a href="settings.html">Properties &amp; Settings</a>