Fix formatting and typos in public/fpdf_structtree.h

Change-Id: I288af4f92014e0a46217c1a461fa0787fb24e02b
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/90510
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
diff --git a/public/fpdf_structtree.h b/public/fpdf_structtree.h
index 0bd56ee..211abdf 100644
--- a/public/fpdf_structtree.h
+++ b/public/fpdf_structtree.h
@@ -62,7 +62,7 @@
 //          buffer         -   A buffer for output the alt text. May be NULL.
 //          buflen         -   The length of the buffer, in bytes. May be 0.
 // Return value:
-//          The number of bytes in the title, including the terminating NUL
+//          The number of bytes in the alt text, including the terminating NUL
 //          character. The number of bytes is returned regardless of the
 //          |buffer| and |buflen| parameters.
 // Comments:
@@ -154,8 +154,8 @@
 //           Get the type (/S) for a given element.
 // Parameters:
 //           struct_element - Handle to the struct element.
-//           buffer        - A buffer for output. May be NULL.
-//           buflen        - The length of the buffer, in bytes. May be 0.
+//           buffer         - A buffer for output. May be NULL.
+//           buflen         - The length of the buffer, in bytes. May be 0.
 // Return value:
 //           The number of bytes in the type, including the terminating NUL
 //           character. The number of bytes is returned regardless of the