Update some docs

CUSTOMIZATION.md

@@ -168,12 +168,12 @@ As output, this script should emit whatever the programs it calls emit.
 - 255: error internal to the script in question
 
 (FIXME: Unsurprisingly, `gofmt` is the only tool I've tested so far that gets
-this right.  That a file should be reformatted isn't an exceptional condition,
-so there's no good reason to signal failure here.
+this right.  It isn't an exceptional condition when a file should be
+reformatted, so there's no good reason to signal failure here.
 
 Even less unsurprisingly, Laravel pint gets it worse than all the others I
-checked; it doesn't distinguish misformatted files from files with actual
-syntax errors.
+checked; it doesn't distinguish files that need to be reformatted from files
+with actual syntax errors.
 
 Anyway, `gofmt` is the obviously the model to follow.  So we should
 probably drop `1`.)