[LDC] move pragma(inline, true); out of function bodies

[thewilsonator]

cc @kinke

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[Geod24]

Can you expand on the rationale ?

[thewilsonator]

see #7463 (comment) and #7463 (comment)

[Geod24]

Thanks. A mention in the commit message would have been great, too, so people can get this information offline / without having to go through 2 indirections :)

[Geod24]

LGTM. Just a minor formatting comment. Feel free to self-merge once fixed.

[Geod24]

@WalterBright : The LDC developers raise an important point. To allow for cross-module inlining, pragma(inline) should be outside of the function body, otherwise the compiler will have to analyze body of functions for non-root modules.
Should we consider deprecating usage of pragma(inline) inside of function body, and restrict it to be on the function's prototype ?