Make edits suggested by Vincent Genot

[tressahelvey]

In SPASE model draft 2.6.0 PDF: Fix type-os.

• Alfven --> Alfvén (at least in the definitions themselves, if not in the title) (Alfven has many occurrences, some, in definition, should be replaced by Alfvén; 2 on p90 and one on p151)
• in AlfvenVelocity : mu should be replaced by mu_0 (page 90)
• typos in : 26P/Grigg?DlSkjellerup, 67P/Churyumov?DlGerasimenko (page 85)
• for Magnetotail : "X < -10Re, in GSE or GSM coordinate system" instead of "X > -10Re" which is wrong ; or we remove this precision (page 152)

[lfb12345]

I have not been able to get the "é" character to work yet. I will still try to do so.

[lfb12345]

Other items have been fixed.

[tressahelvey]

Closing ticket