docs: write prose without dashes or semicolons

Profiles, the wiki, comments, docstrings, command output and schema descriptions carried em-dashes, clause-joining semicolons, unicode arrows, box-drawing banners and check-mark glyphs. Each sentence was rewritten rather than having its character swapped. Hashes, paths, source_ref values and every cited file:line are unchanged, which a comparison of each parsed profile against the previous revision confirms.

validate_pr comments now say PASS and FAIL in words, and source_ref values in a profile's structured blocks render as code. test_prose_style fails if any of these comes back, in tracked files or in the generated site.

tests/test_system_selection.py

@@ -92,7 +92,7 @@ class ADeclinedBuildIsAFailure(unittest.TestCase):
 
 
 class AMistypedPlatformIsNamed(unittest.TestCase):
-    """verify and cross_reference ended a typo on a traceback; generate_pack
+    """verify and cross_reference ended a typo on a traceback, and generate_pack
     ran its whole build first and then said "no pack for batocra"."""
 
     # Every script taking --platform: slots ended on a traceback, and