Informing a regex syntax should include required slash separators (#35234)

Co-authored-by: Ben Ahmady <32935794+subatoi@users.noreply.github.com>

content/search-github/github-code-search/understanding-github-code-search-syntax.md

@@ -317,4 +317,8 @@ If code search guesses wrong, you can always get the search you wanted by using
 
 ## Case sensitivity
 
-By default, code search is case-insensitive. Searching for `True` will include results for _uppercase_ `TRUE` and _lowercase_ `true`. You can do case-sensitive searches by using a regular expression with case insensitivity turned off, for example `(?-i)True`.
+By default, code search is case-insensitive, and results will include both uppercase and lowercase results. You can do case-sensitive searches by using a regular expression with case insensitivity turned off. For example, to search for the string "True", you would use:
+
+```text
+/(?-i)True/
+```