patch 8.2.4928: various white space and cosmetic mistakes

Problem:    Various white space and cosmetic mistakes.
Solution:   Change spaces to tabs, improve comments.
diff --git a/src/channel.c b/src/channel.c
index 52dfaaf..e3b32ee 100644
--- a/src/channel.c
+++ b/src/channel.c
@@ -1996,7 +1996,7 @@
 		    && p[3] == ';')
 	    {
 		// '\a' becomes a NL
-	        while (p < res + (len - 1) && *p != '\a')
+		while (p < res + (len - 1) && *p != '\a')
 		    ++p;
 		// BEL is zero width characters, suppress display mistake
 		// ConPTY (after 10.0.18317) requires advance checking