gitignore: add more vim swap files

1. Ignore "tags" files for all directories.

2. Add more vim swap files(".swo", ".swn").

    https://vimdoc.sourceforge.net/htmldoc/recover.html

    - If this file already exists (e.g., when you are recovering from a crash) a
      warning is given and another extension is used, ".swo", ".swn", etc.

Signed-off-by: wangjianyu3 <wangjianyu3@xiaomi.com>

.gitignore

@@ -25,6 +25,8 @@
 *.rel
 *.src
 *.srec
+*.swn
+*.swo
 *.swp
 *.sym
 *.wsp
@@ -60,7 +62,7 @@
 /nuttx.*
 /nuttx_user*
 /staging
-/tags
+**/tags
 /TAGS
 core
 Make*.dep