Fix an histogramming example (#1154)

* Fix an histogramming example

* Update manual/histograms/index.md

Co-authored-by: ferdymercury <[email protected]>

---------

Co-authored-by: ferdymercury <[email protected]>

Author: couet

manual/histograms/index.md

@@ -128,10 +128,10 @@ For creating variable bins histograms:
 
 {% highlight C++ %}
    double binEdges[] = { 0.0, 0.2, 0.5, 1., 2., 4. };
-   TH1* h1 = new TH1D("h1", "h1 title", 6, binEdges );
-   TH2* h2 = new TH2D("h2", "h2 title", 6, binEdges , 30, -1.5, 3.5);
+   TH1* h1 = new TH1D("h1", "h1 title", 5, binEdges );
+   TH2* h2 = new TH2D("h2", "h2 title", 5, binEdges , 30, -1.5, 3.5);
 {% endhighlight %}
-note that the array of bin edges should be of size `nbins+1` , since it contains the lower and upper range axis values.
+note that the array of bin edges should be of size `nbins+1`, since it contains the lower and upper range axis values.
 
 For creating a profile histograms passing the range in the profiled variable (e..g .Y for a `TProfille`) is optional:
 {% highlight C++ %}