patch 8.2.5029: "textlock" is always zero

Problem:    "textlock" is always zero.
Solution:   Remove "textlock" and rename "textwinlock" to "textlock".
            (closes #10489)
diff --git a/src/indent.c b/src/indent.c
index ccf4aa8..7598c1c 100644
--- a/src/indent.c
+++ b/src/indent.c
@@ -1872,7 +1872,7 @@
     set_vim_var_nr(VV_LNUM, curwin->w_cursor.lnum);
     if (use_sandbox)
 	++sandbox;
-    ++textwinlock;
+    ++textlock;
     current_sctx = curbuf->b_p_script_ctx[BV_INDE];
 
     // Need to make a copy, the 'indentexpr' option could be changed while
@@ -1886,7 +1886,7 @@
 
     if (use_sandbox)
 	--sandbox;
-    --textwinlock;
+    --textlock;
     current_sctx = save_sctx;
 
     // Restore the cursor position so that 'indentexpr' doesn't need to.