Comments: Add support for new format (#4576)

The new comment format is similar to the description's commandRuns.

This should fix the issues with most comments but there are still
some more changes that would need to be made like adding support for
formatting (bold, italic, underline) and channel emojis.

Fixes issue 4566

src/invidious/videos/description.cr

@@ -7,7 +7,19 @@ private def copy_string(str : String::Builder, iter : Iterator, count : Int) : I
     cp = iter.next
     break if cp.is_a?(Iterator::Stop)
 
-    str << cp.chr
+    if cp == 0x26 # Ampersand (&)
+      str << "&amp;"
+    elsif cp == 0x27 # Single quote (')
+      str << "&#39;"
+    elsif cp == 0x22 # Double quote (")
+      str << "&quot;"
+    elsif cp == 0x3C # Less-than (<)
+      str << "&lt;"
+    elsif cp == 0x3E # Greater than (>)
+      str << "&gt;"
+    else
+      str << cp.chr
+    end
 
     # A codepoint from the SMP counts twice
     copied += 1 if cp > 0xFFFF