Tamil: add positioning of marks on U+25CC

[emuller-amazon]

Currently, there is no support to position marks with U+25CC as the base. <25CC, 0BC0> works more or less by accident, but <25CC, 0B82> has the anusvara on the right side of the dotted circle rather than on top of it.

[roozbehp]

Thanks a lot @emuller-amazon for the report. This is indeed an important issue for Android too.

[jungshik]

@JelleBosmaMT

[JelleBosmaMT]

Why would I add mark attachment for <25CC, 0BC0> if that would look exactly the same as without mark attachment?
I have it on good authority that anusvara 0B82 is not used for Tamil or anything else: www.unicode.org/L2/L2012/12018-tamil-anusvara-depr.pdf. Noto Sans Tamil has it as a spacing glyph, so that it cannot be confused with a Virama.

[nizarsq]

I agree with @JelleBosmaMT, they look exactly the same as without mark attachment. This issue seems to be fixed.