Implement Curved Pilcrow (+ minor fix)

[Logo121]

❡¶⁋⁌⁍

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• Closes Curved Pilcrow Sign (¶) plus a hard Unicode character (❡). #2045 and probably Custom build: bold italic f has some artifact #2628
• Rewritten Pilcrow because the metrics and implementation are kinda awkward (uses sw directly for vertical stroke width, etc)
• The Dingbat glyph is loosely based on the Segoe UI Symbol version which is the most simplistic version I could easily find.
• Minor fix on the f hook to prevent the artifact in Custom build: bold italic f has some artifact #2628, which will probably happen when the hook is too large (or the descender space too small.)
  • I didn't really try to reproduce the artifact, but it doesn't seem to cause any problem using the metric override in the original issue (xHeight = 550) so I assume this did the trick.