patch 8.2.0509: various code is not properly tested.

Problem:    various code is not properly tested.
Solution:   Add more tests. (Yegappan Lakshmanan, closes #5871)
diff --git a/src/main.c b/src/main.c
index 2d61c06..79973cb 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1966,7 +1966,7 @@
 #endif
     }
 
-    // Checking for "ex" here may catch some weir names, such as "vimex" or
+    // Checking for "ex" here may catch some weird names, such as "vimex" or
     // "viewex", we assume the user knows that.
     if (STRNICMP(initstr, "ex", 2) == 0)
     {