patch 9.1.0747: various typos in repo found

Problem:  various typos in repo found
Solution: Fix typos (zeertzjq)

closes: #15749

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/commondumps.vim b/src/testdir/commondumps.vim
index ed70280..cfe426c 100644
--- a/src/testdir/commondumps.vim
+++ b/src/testdir/commondumps.vim
@@ -23,7 +23,7 @@
 
 # Search for the "failed" directory in the passed _subtreedirname_ directories
 # (usually "\<src\>" or "\<syntax\>") and, if found, select its passed _count_
-# occurence, add all its "*.dump" files to the argument list and list them;
+# occurrence, add all its "*.dump" files to the argument list and list them;
 # also define a BufRead autocommand that would invoke "Render()" for every
 # "*.dump" file.
 def g:Init(subtreedirname: string, count: number)