Jira reader: improve icon conversion

Icons are now converted as follows: `(/)` to ✔, `(x)` to ❌, `(!)` to
❗, `(+)` to ➕, `(-)` to ➖, `(off)` to 🌙, and `(*)` to ☆. The new
icons render well in most fonts. Furthermore, the UTF-8 characters all
fit into 4-bytes.

Closes: #6264

src/Text/Pandoc/Readers/Jira.hs

@@ -182,18 +182,18 @@ iconUnicode = \case
   Jira.IconThumbsUp        -> "👍"
   Jira.IconThumbsDown      -> "👎"
   Jira.IconInfo            -> "ℹ"
-  Jira.IconCheckmark       -> "✓"
-  Jira.IconX               -> "🅇"
-  Jira.IconAttention       -> "⚠"
-  Jira.IconPlus            -> "⊞"
-  Jira.IconMinus           -> "⊟"
-  Jira.IconQuestionmark    -> "﹖"
+  Jira.IconCheckmark       -> "✔"
+  Jira.IconX               -> "❌"
+  Jira.IconAttention       -> "❗"
+  Jira.IconPlus            -> "➕"
+  Jira.IconMinus           -> "➖"
+  Jira.IconQuestionmark    -> "❓"
   Jira.IconOn              -> "💡"
-  Jira.IconOff             -> "💡"
-  Jira.IconStar            -> "★"
-  Jira.IconStarRed         -> "★"
-  Jira.IconStarGreen       -> "★"
-  Jira.IconStarBlue        -> "★"
-  Jira.IconStarYellow      -> "★"
+  Jira.IconOff             -> "🌙"
+  Jira.IconStar            -> "⭐"
+  Jira.IconStarRed         -> "⭐"
+  Jira.IconStarGreen       -> "⭐"
+  Jira.IconStarBlue        -> "⭐"
+  Jira.IconStarYellow      -> "⭐"
   Jira.IconFlag            -> "⚑"
   Jira.IconFlagOff         -> "⚐"

test/jira-reader.native

@@ -113,7 +113,7 @@ Pandoc (Meta {unMeta = fromList []})
 ,HorizontalRule
 ,Header 1 ("",[],[]) [Str "Dashes,",Space,Str "and",Space,Str "emoticons"]
 ,Para [Str "Some",Space,Str "dashes:",Space,Str "one",Space,Str "\8211",Space,Str "two",Space,Str "\8212",Space,Str "three."]
-,Para [Str "Sure",Space,Str "\10003",LineBreak,Str "Nope",Space,Str "\127303"]
+,Para [Str "Sure",Space,Str "\10004",LineBreak,Str "Nope",Space,Str "\10060"]
 ,Para [Str "Nice",Space,Str "\128515"]
 ,Para [Str "Capital",Space,Str "d:D"]
 ,HorizontalRule