Semantics of 'static lifetime are not explained

[ettolrach]

It's never explained what 'static actually means. Currently, the only definition of 'static given is two examples of what could be 'static. Namely:

• "Both constant and static declarations of reference types have implicit 'static lifetimes unless an explicit lifetime is specified." https://github.com/rust-lang/reference/blob/b3ce60628c6f55ab8ff3dba9f3d20203df1c0dee/src/lifetime-elision.md?plain=1#L185 https://github.com/rust-lang/reference/blob/b3ce60628c6f55ab8ff3dba9f3d20203df1c0dee/src/items/constant-items.md?plain=1#L24
• "string literals always have 'static lifetime." https://github.com/rust-lang/reference/blob/b3ce60628c6f55ab8ff3dba9f3d20203df1c0dee/src/subtyping.md?plain=1#L14 https://github.com/rust-lang/reference/blob/b3ce60628c6f55ab8ff3dba9f3d20203df1c0dee/src/expressions/literal-expr.md?plain=1#L176

The exact semantics of 'static should be made clear.