patch 8.2.0953: spell checking doesn't work for CamelCased words

Problem:    Spell checking doesn't work for CamelCased words.
Solution:   Add the "camel" value in the new option 'spelloptions'.
            (closes #1235)
diff --git a/runtime/doc/spell.txt b/runtime/doc/spell.txt
index d4f542d..3f8302b 100644
--- a/runtime/doc/spell.txt
+++ b/runtime/doc/spell.txt
@@ -215,6 +215,9 @@
 line may be postponed.  Use |CTRL-L| when needed.  Also see |set-spc-auto| for
 how it can be set automatically when 'spelllang' is set.
 
+The 'spelloptions' option has a few more flags that influence the way spell
+checking works.
+
 Vim counts the number of times a good word is encountered.  This is used to
 sort the suggestions: words that have been seen before get a small bonus,
 words that have been seen often get a bigger bonus.  The COMMON item in the