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/options.txt b/runtime/doc/options.txt
index 9f9ae94..d8e3192 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -7105,6 +7105,16 @@
 	up to the first character that is not an ASCII letter or number and
 	not a dash.  Also see |set-spc-auto|.
 
+						*'spelloptions'* *'spo'*
+'spelloptions' 'spo'	string	(default "")
+			local to buffer
+			{not available when compiled without the |+syntax|
+			feature}
+	A comma separated list of options for spell checking:
+	   camel	When a word is CamelCased, assume "Cased" is a
+			separate word: every upper-case character in a word
+			that comes after a lower case character indicates the
+			start of a new word.
 
 						*'spellsuggest'* *'sps'*
 'spellsuggest' 'sps'	string	(default "best")