[arabic_high_hamza] Make the size of high hamza a warning

It seems to be debatable since high hamza is used also in Kazakh where
small high hamza is acceptable. Instead of complicated and possibly
error prune language detection, lets make it a warning.

CHANGELOG.md

@@ -9,7 +9,7 @@ A more detailed list of changes is available in the corresponding milestones for
 ### Changes to existing checks
 ### On the Universal profile.
   - **[no_debugging_tables]** and **[vttclean]** are now merged into unwanted_tables. (issues #4972 and #4975)
-  - **[arabic_high_hamza]** now checks U+0674 ARABIC LETTER HIGH HAMZA and not U+0675 ARABIC LETTER HIGH HAMZA ALEF. (issue #4290)
+  - **[arabic_high_hamza]** now checks U+0674 ARABIC LETTER HIGH HAMZA and not U+0675 ARABIC LETTER HIGH HAMZA ALEF, and the size check of _high hamza_ is now a warning instead of a fauilre. (issue #4290)
 
 ### On the OpenType Profile
   - **[opentype/slant_direction]:** SKIP instead of ERROR if a font does not contain 'H' (PR #4969)

Lib/fontbakery/checks/arabic_high_hamza.py

@@ -1,4 +1,4 @@
-from fontbakery.prelude import FAIL, SKIP, Message, check
+from fontbakery.prelude import FAIL, SKIP, WARN, Message, check
 from fontbakery.utils import get_glyph_name
 
 
@@ -70,9 +70,9 @@ def check_arabic_high_hamza(ttFont):
     high_hamza_area = area_pen.value
 
     if abs((high_hamza_area - hamza_area) / hamza_area) > 0.1:
-        yield FAIL, Message(
+        yield WARN, Message(
             "glyph-area",
             "The arabic letter high hamza (U+0674) should have roughly"
-            " the same size the arabic letter hamza (U+0621),"
-            " but a different glyph outline area was detected.",
+            " the same size the arabic letter hamza (U+0621) while raised"
+            " above baseline, but a different glyph outline area was detected.",
         )