SDL_ttf: added missing doc for 'previous' param of TTF_GetPreviousTextSubString.

From 71fd7f9c6d432bd63743dcec72d623a28f9556b1 Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Wed, 28 May 2025 14:37:02 +0300
Subject: [PATCH] added missing doc for 'previous' param of
 TTF_GetPreviousTextSubString.

(cherry picked from commit ffa54ca2ec6b89b4f6dc92ab113484cfa2ccc3a7)
---
 include/SDL3_ttf/SDL_ttf.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/SDL3_ttf/SDL_ttf.h b/include/SDL3_ttf/SDL_ttf.h
index 40f7eca9..01460386 100644
--- a/include/SDL3_ttf/SDL_ttf.h
+++ b/include/SDL3_ttf/SDL_ttf.h
@@ -2692,6 +2692,8 @@ extern SDL_DECLSPEC bool SDLCALL TTF_GetTextSubStringForPoint(TTF_Text *text, in
  *
  * \param text the TTF_Text to query.
  * \param substring the TTF_SubString to query.
+ * \param previous a pointer filled in with the previous substring in the text
+ *                 object.
  * \returns true on success or false on failure; call SDL_GetError() for more
  *          information.
  *