Work around bug in font-patcher --custom

[why]
The --custom option seems to be broken for fonts with 'invalid' glyph,
which most fonts that fontforge generates have.

[how]
Use sfd instead of ttf, where to invalid glyph is not added.

Signed-off-by: Fini Jastrow <[email protected]>

Author: Finii

do_generate

@@ -22,7 +22,7 @@ fi
 PWD=$( pwd )
 
 rm -f C*.ttf
-fontforge -script "${PWD}/font-patcher" --careful "${3}" --custom "${PWD}/SomeExtraSymbols.otf" --no-progressbars "${PWD}/ttf/static/${4}" "${2}" --outputdir "${PWD}" | tee "process${1}.log"
+fontforge -script "${PWD}/font-patcher" --careful "${3}" --custom SomeExtraSymbols.sfd --no-progressbars "${PWD}/ttf/static/${4}" "${2}" --outputdir "${PWD}" | tee "process${1}.log"
 
 if [ -z "${OURVERSION}" ]; then
     # Github CI sets this variable, but this can be useful for manual calls:

extract-extra-glyphs

@@ -2,4 +2,4 @@ Open($2);
 SelectAll();
 SelectFewer(0u26A1);
 Clear();
-Generate($1 + "/src/glyphs/SomeExtraSymbols.otf");
+Save($1 + "/src/glyphs/SomeExtraSymbols.sfd");