Adding new small graph structures

[Fightlapa]

CC: @dcoudert

Component: graph theory

Author: Jakub Jabłoński

Branch/Commit: 5ec6133

Reviewer: David Coudert

Issue created by migration from https://trac.sagemath.org/ticket/30159

[Fightlapa]

Branch: public/graphs/new_basic_structures

[Fightlapa]

Commit: 23a7baa

[Fightlapa]

Author: Jakub Jabłoński

[Fightlapa]

New commits:

23a7baa

Adding fork graph, gem graph and bull graph to graph list

[dcoudert]

comment:7

Hello,

please do the following changes to the 3 methods.

• use Return instead of Returns

-    Returns a gem graph with 5 nodes.
+    Returns a gem graph with 5 nodes.

• this form is more usual. I know other forms are used in basic.py, but this will be unified in the future.

-    EXAMPLES: Construct and show a gem graph
-
-    ::
+    EXAMPLES:
+
+    Construct and show a gem graph::

[sagetrac-git]

Changed commit from 23a7baa to 1838d26

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

1838d26

Fixed docs of new graph structures

[dcoudert]

Reviewer: David Coudert

[dcoudert]

comment:9

LGTM.

[vbraun]

comment:10

See patchbot

[dcoudert]

comment:11

I didn't see that one, sorry

sage -t --long --random-seed=0 src/sage/graphs/graph_list.py
**********************************************************************
File "src/sage/graphs/graph_list.py", line 321, in sage.graphs.graph_list.show_graphs
Failed example:
    len(glist)
Expected:
    14
Got:
    17

Also, I suggest to add # long time after g.show() like

-        sage: g.show()
+        sage: g.show()  # long time

it's not interesting when running doctests to display these graphs, but it is good for the documentation.

[sagetrac-git]

Changed commit from 1838d26 to 5ec6133

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

5ec6133

Added long time comment in graph show method, fixed test

[dcoudert]

comment:13

LGTM.

[vbraun]

Changed branch from public/graphs/new_basic_structures to 5ec6133