Update default.md (#2245)
Update default.md (#2245)

Making documentation consistent between sources:  Issue Typo! #650

In (grav-learn/pages/01.basics/04.basic-tutorial/docs.md) the text under the heading Adding a New Page is 02.mypage 
In (grav/user/pages/01.home/default.md) the text under the heading Adding a New Page is 03.mypage
Vivalldi/grav,tomzx/blog.tomrochette.com,tomzx/blog.tomrochette.com,Vivalldi/grav,tomzx/blog.tomrochette.com,stell/grav,tomzx/blog.tomrochette.com,getgrav/grav,getgrav/grav