Reword docs for Fiddle::Function#call [ci skip]

I'm using `<code>` instead of `+` since `+` only works when it encloses
a single word.

1 files changed, 2 insertions, 3 deletions

diff --git a/ext/fiddle/function.c b/ext/fiddle/function.c
index 1d82bc8a3e..afa95d7193 100644
--- a/ext/fiddle/function.c
+++ b/ext/fiddle/function.c
@@ -451,9 +451,8 @@ Init_fiddle_function(void)
      * Caller must ensure the underlying function is called in a
      * thread-safe manner if running in a multi-threaded process.
      *
-     * Note that it is not thread-safe to use this method to
-     * directly or indirectly call many Ruby C-extension APIs unless
-     * you don't pass +need_gvl: true+ to Fiddle::Function#new.
+     * Note that many Ruby C-extension APIs are thread-safe to call
+     * only when the Function is constructed with <code>need_gvl: true</code>.
      *
      * For an example see Fiddle::Function
      *