Improve fsselection_matches_macstyle reporting

Mention relevant bit values on the log messages.

com.adobe.fonts/check/fsselection_matches_macstyle
On the Open Type profile.

(PR #4570)

CHANGELOG.md

@@ -28,6 +28,7 @@ A more detailed list of changes is available in the corresponding milestones for
   - **[com.google.fonts/check/mac_style]:** Skip if font style can not be determined. (issue #4349)
   - **[com.google.fonts/check/family/panose_familytype]:** Add rationale and improve message when there are inconsistencies. (PR #4570)
   - **[com.google.fonts/check/xavgcharwidth]:** Added rationale. Also, when glyphs needed to compute xAvgCharWidth are missing, it is considered critical, so it is now results in a FATAL-level result. (PR #4570)
+  - **[com.adobe.fonts/check/fsselection_matches_macstyle]:** Improve log messages to include the bit values. (PR #4570)
 
 
 ## 0.12.0a2 (2024-Feb-21)

Lib/fontbakery/checks/opentype/os2.py

@@ -199,15 +199,19 @@ def com_adobe_fonts_check_fsselection_matches_macstyle(ttFont):
         failed = True
         yield FAIL, Message(
             "fsselection-macstyle-bold",
-            "The OS/2.fsSelection and head.macStyle bold settings do not match.",
+            "The OS/2.fsSelection and head.macStyle bold settings do not match:\n\n"
+            f"* OS/2.fsSelection: BOLD is {'not ' if not os2_bold else ''}set\n"
+            f"* head.macStyle: BOLD is {'not ' if not head_bold else ''}set",
         )
     head_italic = (ttFont["head"].macStyle & MacStyle.ITALIC) != 0
     os2_italic = (ttFont["OS/2"].fsSelection & FsSelection.ITALIC) != 0
     if head_italic != os2_italic:
         failed = True
         yield FAIL, Message(
             "fsselection-macstyle-italic",
-            "The OS/2.fsSelection and head.macStyle italic settings do not match.",
+            "The OS/2.fsSelection and head.macStyle italic settings do not match.\n\n"
+            f"* OS/2.fsSelection: ITALIC is {'not ' if not os2_italic else ''}set\n"
+            f"* head.macStyle: ITALIC is {'not ' if not head_italic else ''}set",
         )
     if not failed:
         yield PASS, (