Only trim trailing spaces to avoid breakage in storyboard parsing

osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs

@@ -67,16 +67,14 @@ protected override void ParseStreamInto(LineBufferedReader stream, Beatmap beatm
 
         protected override void ParseLine(Beatmap beatmap, Section section, string line)
         {
-            var strippedLine = StripComments(line);
-
             switch (section)
             {
                 case Section.General:
-                    handleGeneral(strippedLine);
+                    handleGeneral(line);
                     return;
 
                 case Section.Editor:
-                    handleEditor(strippedLine);
+                    handleEditor(line);
                     return;
 
                 case Section.Metadata:
@@ -84,19 +82,19 @@ protected override void ParseLine(Beatmap beatmap, Section section, string line)
                     return;
 
                 case Section.Difficulty:
-                    handleDifficulty(strippedLine);
+                    handleDifficulty(line);
                     return;
 
                 case Section.Events:
-                    handleEvent(strippedLine);
+                    handleEvent(line);
                     return;
 
                 case Section.TimingPoints:
-                    handleTimingPoint(strippedLine);
+                    handleTimingPoint(line);
                     return;
 
                 case Section.HitObjects:
-                    handleHitObject(strippedLine);
+                    handleHitObject(line);
                     return;
             }
 

osu.Game/Beatmaps/Formats/LegacyDecoder.cs

@@ -36,7 +36,7 @@ protected override void ParseStreamInto(LineBufferedReader stream, T output)
                 if (ShouldSkipLine(line))
                     continue;
 
-                line = line.Trim();
+                line = StripComments(line).TrimEnd();
 
                 if (line.StartsWith('[') && line.EndsWith(']'))
                 {
@@ -73,8 +73,6 @@ protected virtual void OnBeginNewSection(Section section)
 
         protected virtual void ParseLine(T output, Section section, string line)
         {
-            line = StripComments(line);
-
             switch (section)
             {
                 case Section.Colours:

osu.Game/Beatmaps/Formats/LegacyStoryboardDecoder.cs

@@ -45,8 +45,6 @@ protected override void ParseStreamInto(LineBufferedReader stream, Storyboard st
 
         protected override void ParseLine(Storyboard storyboard, Section section, string line)
         {
-            line = StripComments(line);
-
             switch (section)
             {
                 case Section.General:

osu.Game/Skinning/LegacyManiaSkinDecoder.cs

@@ -31,8 +31,6 @@ protected override void OnBeginNewSection(Section section)
 
         protected override void ParseLine(List<LegacyManiaSkinConfiguration> output, Section section, string line)
         {
-            line = StripComments(line);
-
             switch (section)
             {
                 case Section.Mania: