Change literal minus ‘−’ to HTML entity ‘−’

So that if people accidentally delete the character, they won’t re-type it as a hyphen, which would cause bugs.

I changed ‘+’ too, even though it won’t be re-typed incorrectly, so that it is easier to see when plus is used as a symbol for the button, and when it is used as an operator in code. It also makes it clearer that the use of an entity for minus is on purpose, so people won’t be tempted to replace the entity incorrectly with a hyphen character.

src/librustdoc/html/render.rs

@@ -1460,7 +1460,7 @@ impl<'a> fmt::Display for Item<'a> {
         try!(write!(fmt, "<span class='out-of-band'>"));
         try!(write!(fmt,
         r##"<span id='render-detail'>
-            <a id="toggle-all-docs" href="#" title="collapse all docs">[−]</a>
+            <a id="toggle-all-docs" href="#" title="collapse all docs">[&minus;]</a>
         </span>"##));
 
         // Write `src` tag

src/librustdoc/html/static/main.js

@@ -808,20 +808,20 @@
 
     $("#toggle-all-docs").on("click", function() {
         var toggle = $("#toggle-all-docs");
-        if (toggle.html() == "[−]") {
-            toggle.html("[+]");
+        if (toggle.html() == "[−]") {
+            toggle.html("[+]");
             toggle.attr("title", "expand all docs");
             $(".docblock").hide();
             $(".toggle-label").show();
             $(".toggle-wrapper").addClass("collapsed");
-            $(".collapse-toggle").children(".inner").html("+");
+            $(".collapse-toggle").children(".inner").html("+");
         } else {
-            toggle.html("[−]");
+            toggle.html("[−]");
             toggle.attr("title", "collapse all docs");
             $(".docblock").show();
             $(".toggle-label").hide();
             $(".toggle-wrapper").removeClass("collapsed");
-            $(".collapse-toggle").children(".inner").html("−");
+            $(".collapse-toggle").children(".inner").html("−");
         }
     });
 
@@ -835,20 +835,20 @@
             if (relatedDoc.is(":visible")) {
                 relatedDoc.slideUp({duration:'fast', easing:'linear'});
                 toggle.parent(".toggle-wrapper").addClass("collapsed");
-                toggle.children(".inner").html("+");
+                toggle.children(".inner").html("+");
                 toggle.children(".toggle-label").fadeIn();
             } else {
                 relatedDoc.slideDown({duration:'fast', easing:'linear'});
                 toggle.parent(".toggle-wrapper").removeClass("collapsed");
-                toggle.children(".inner").html("−");
+                toggle.children(".inner").html("−");
                 toggle.children(".toggle-label").hide();
             }
         }
     });
 
     $(function() {
         var toggle = $("<a/>", {'href': 'javascript:void(0)', 'class': 'collapse-toggle'})
-            .html("[<span class='inner'>−</span>]");
+            .html("[<span class='inner'>&minus;</span>]");
 
         $(".method").each(function() {
             if ($(this).next().is(".docblock") ||