Fix font rendering for long glyphs

[Yaraslaut]

Closes #1349

Bug is happening due to bad offset of the glyph that is positioned after the glyph with non-standard advance

for MonaspiceKrNerdFont

====================================
tryShape: font=0, codepoints="===a"
gpos: (10113+0+0|32+0)
gpos: (66+0+0|10+0)
====================================
tryShape: font=0, codepoints="===a:"
gpos: (10113+0+0|32+0)
gpos: (66+0+0|10+0)
gpos: (27+0+0|10+0)

While for CascadiaCode

====================================
tryShape: font=0, codepoints="===a"
gpos: (2665+0+0|10+0)
gpos: (3125+0+0|10+0)
gpos: (3125+0+0|10+0)
gpos: (225+0+0|10+0)
====================================
tryShape: font=0, codepoints="===a:"
gpos: (2665+0+0|10+0)
gpos: (3125+0+0|10+0)
gpos: (3125+0+0|10+0)
gpos: (225+0+0|10+0)
gpos: (1864+0+0|10+0)

So while for CascadiaCode ligature is represented as separate codepoints, Monaspice merges them together with bigger advance

[christianparpart]

Many thanks, @Yaraslaut :)