runtime(doc): Fix typos in several documents (#13420)

* Fix typos in several documents
* Update runtime/doc/terminal.txt

Co-authored-by: K.Takata <kentkt@csc.jp>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/intro.txt b/runtime/doc/intro.txt
index b19c306..f4ddb08 100644
--- a/runtime/doc/intro.txt
+++ b/runtime/doc/intro.txt
@@ -184,7 +184,7 @@
 ==============================================================================
 3. Credits						*credits* *author*
 
-Most of Vim was created by Bram Moolenaar <Bram@vim.org> |Bram-Moolenaar|
+Most of Vim was created by Bram Moolenaar <Bram@vim.org> |Bram-Moolenaar|.
 
 Parts of the documentation come from several Vi manuals, written by:
 	W.N. Joy
@@ -217,7 +217,8 @@
 	Bill Foster		Athena GUI port (later removed)
 	Google			Let Bram work on Vim one day a week
 	Loic Grenie		xvim (ideas for multi windows version)
-	Sven Guckes		Vim promoter and previous WWW page maintainer |Sven-Guckes|
+	Sven Guckes		Vim promoter and previous WWW page maintainer
+				|Sven-Guckes|
 	Darren Hiebert		Exuberant ctags
 	Jason Hildebrand	GTK+ 2 port
 	Bruce Hunsaker		improvements for VMS port