patch 8.2.3967: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move more errors to errors.h.
diff --git a/src/if_tcl.c b/src/if_tcl.c
index 75fa858..cc48c8e 100644
--- a/src/if_tcl.c
+++ b/src/if_tcl.c
@@ -215,7 +215,7 @@
     if (!(hTclLib = load_dll(libname)))
     {
 	if (verbose)
-	    semsg(_(e_loadlib), libname, load_dll_error());
+	    semsg(_(e_could_not_load_library_str_str), libname, load_dll_error());
 	return FAIL;
     }
     for (i = 0; tcl_funcname_table[i].ptr; ++i)
@@ -226,7 +226,7 @@
 	    close_dll(hTclLib);
 	    hTclLib = NULL;
 	    if (verbose)
-		semsg(_(e_loadfunc), tcl_funcname_table[i].name);
+		semsg(_(e_could_not_load_library_function_str), tcl_funcname_table[i].name);
 	    return FAIL;
 	}
     }