libsmartcols: add 'Since' tag for gtkdoc for some functions

Signed-off-by: Igor Gnatenko <i.gnatenko.brain@gmail.com>

libsmartcols/docs/libsmartcols-docs.xml

@@ -49,4 +49,8 @@ available from ftp://ftp.kernel.org/pub/linux/utils/util-linux/.
     <title>API Index</title>
     <xi:include href="xml/api-index-full.xml"><xi:fallback /></xi:include>
   </index>
+  <index role="2.28">
+    <title>Index of new symbols in 2.28</title>
+    <xi:include href="xml/api-index-2.28.xml"><xi:fallback /></xi:include>
+  </index>
 </book>

libsmartcols/src/line.c

@@ -394,6 +394,8 @@ int scols_line_set_data(struct libscols_line *ln, size_t n, const char *data)
  * The same as scols_line_set_data() but cell is referenced by column object.
  *
  * Returns: 0, a negative value in case of an error.
+ *
+ * Since: 2.28
  */
 int scols_line_set_column_data(struct libscols_line *ln,
 			       struct libscols_column *cl,
@@ -428,6 +430,8 @@ int scols_line_refer_data(struct libscols_line *ln, size_t n, char *data)
  * The same as scols_line_refer_data() but cell is referenced by column object.
  *
  * Returns: 0, a negative value in case of an error.
+ *
+ * Since: 2.28
  */
 int scols_line_refer_column_data(struct libscols_line *ln,
 			       struct libscols_column *cl,
@@ -474,5 +478,3 @@ err:
 	scols_unref_line(ret);
 	return NULL;
 }
-
-

libsmartcols/src/symbols.c

@@ -151,6 +151,8 @@ int scols_symbols_set_right(struct libscols_symbols *sb, const char *str)
  * A multibyte chars are not supported yet.
  *
  * Returns: 0, a negative value in case of an error.
+ *
+ * Since: 2.28
  */
 int scols_symbols_set_title_padding(struct libscols_symbols *sb, const char *str)
 {

libsmartcols/src/table.c

@@ -132,6 +132,8 @@ int scols_table_set_name(struct libscols_table *tb, const char *name)
  * The table title is used to print header of table.
  *
  * Returns: 0, a negative number in case of an error.
+ *
+ * Since: 2.28
  */
 int scols_table_set_title(struct libscols_table *tb, const char *title, unsigned int position, const char *color)
 {
@@ -939,6 +941,8 @@ int scols_table_enable_maxout(struct libscols_table *tb, int enable)
  * Never continue on next line, remove last column(s) when too large, truncate last column.
  *
  * Returns: 0 on success, negative number in case of an error.
+ *
+ * Since: 2.28
  */
 int scols_table_enable_nowrap(struct libscols_table *tb, int enable)
 {