Close verbatim in 3rd column header to fix table rendering

The key change is in l. 14 only. Lines 15-20 only add single space.

Change [StringSplitter](https://errorprone.info/bugpattern/StringSplitter)

![ep-before](https://user-images.githubusercontent.com/11896137/155527255-5e401bd8-9eab-4117-b99c-2e10d77039a9.png)

to

![ep-after](https://user-images.githubusercontent.com/11896137/155527292-7120c01d-ced4-465e-ab4b-91d8e6c35ae5.png)

Fixes #3008

COPYBARA_INTEGRATE_REVIEW=#3008 from pzygielo:splitter 77882b6
PiperOrigin-RevId: 435397302

docs/bugpattern/StringSplitter.md

@@ -11,13 +11,13 @@ The result is `[""]` and `[]`!
 
 More examples:
 
-input    | `input.split(":")`  | `Pattern.compile(":").split(input) | `Splitter.on(':').split(input)`
--------- | ------------------- | ---------------------------------- | -------------------------------
-`""`     | `[""]`              | `[""]`                             | `[""]`
-`":"`    | `[]`                | `[]`                               | `["", ""]`
-`":::"`  | `[]`                | `[]`                               | `["", "", "", ""]`
-`"a:::"` | `["a"]`             | `["a"]`                            | `["a", "", "", ""]`
-`":::b"` | `["", "", "", "b"]` | `["", "", "", "b"]`                | `["", "", "", "b"]`
+input    | `input.split(":")`  | `Pattern.compile(":").split(input)` | `Splitter.on(':').split(input)`
+-------- | ------------------- | ----------------------------------- | -------------------------------
+`""`     | `[""]`              | `[""]`                              | `[""]`
+`":"`    | `[]`                | `[]`                                | `["", ""]`
+`":::"`  | `[]`                | `[]`                                | `["", "", "", ""]`
+`"a:::"` | `["a"]`             | `["a"]`                             | `["a", "", "", ""]`
+`":::b"` | `["", "", "", "b"]` | `["", "", "", "b"]`                 | `["", "", "", "b"]`
 
 Prefer either: