change twitter to instagram in examples for multigraph and for graph match

[ebridge2]

• [x] multigraph model section
• [x] multigraph fitting section
• [x] GM section
• [x] supplement (jesus spectral section)
• [x] Chapter 1 stuff

[ebridge2]

Reassigned to @loftusa just to observe the changes and look over briefly before closing

[loftusa]

done