Add dotted circle (U+25CC)

[tphinney]

Ensure dotted circle glyph is present and can attach marks. Check ID: com.google.fonts/check/dotted_circle The dotted circle character (U+25CC) is inserted by shaping engines before mark glyphs which do not have an associated base, especially in the context of broken syllabic clusters.

For fonts containing combining marks, it is recommended that the dotted circle character be included so that these isolated marks can be displayed properly; for fonts supporting complex scripts, this should be considered mandatory.

Additionally, when a dotted circle glyph is present, it should be able to display all marks correctly, meaning that it should contain anchors for all attaching marks.

⚠️ ScienceGothic[YOPQ,slnt,wdth,wght].ttf ⚠️ WARN No dotted circle glyph present [code: missing-dotted-circle]