correct title for notcurses_progbar.3 link in index.html

doc/man/index.html

@@ -57,7 +57,7 @@
    <a href="notcurses_palette.3.html">notcurses_palette</a>—operations on notcurses palettes<br/>
    <a href="notcurses_plane.3.html">notcurses_plane</a>—operations on <tt>ncplane</tt> objects<br/>
    <a href="notcurses_plot.3.html">notcurses_plot</a>—drawing histograms and lineplots<br/>
-   <a href="notcurses_progbar.3.html">notcurses_plot</a>—drawing progress bars<br/>
+   <a href="notcurses_progbar.3.html">notcurses_progbar</a>—drawing progress bars<br/>
    <a href="notcurses_reader.3.html">notcurses_reader</a>—high-level widget for collecting input<br/>
    <a href="notcurses_refresh.3.html">notcurses_refresh</a>—refresh an externally-damaged display<br/>
    <a href="notcurses_render.3.html">notcurses_render</a>—sync the physical display<br/>