Remove trailing \ from last line of exported function macros

[imciner2]

The slash shouldn't be included on the last line of the macro, since it tells the compiler the next line should be considered as part of the current macro. This PR removes the slash from the last line of two macros inside jl_exported_funcs.inc, which also makes them consistent in style with the macros in the jl_exported_data.inc file. This also triggered a GCC warning on my machine because one of them was at the end of the file:

    CC cli/loader_lib.o
In file included from /home/imcinerney/dev/julia/main/v1.6/cli/jl_exports.h:6,
                 from /home/imcinerney/dev/julia/main/v1.6/cli/loader_lib.c:10:
/home/imcinerney/dev/julia/main/v1.6/cli/../src/jl_exported_funcs.inc:1:31: warning: backslash-newline at end of file
    1 | #define JL_EXPORTED_FUNCS(XX) \
      |                                
    CC cli/loader_trampolines.o
In file included from /home/imcinerney/dev/julia/main/v1.6/cli/trampolines/trampolines_x86_64.S:2:
/home/imcinerney/dev/julia/main/v1.6/cli/trampolines/../../src/jl_exported_funcs.inc:1:31: warning: backslash-newline at end of file
    1 | #define JL_EXPORTED_FUNCS(XX) \
      |                                

Note this warning clean-up is not contained in #44350 already.

[vtjnash]

There was supposed to be a trailing newline in this file to avoid the warning. Is that missing now?

[imciner2]

There doesn't appear to be a newline in the fie on master, but I think even if the newline silences removing the slashes is still good to remove them because then it makes these two macros consistent with the data exporting macros and the JL_RUNTIME_EXPORTED_FUNCS_WIN macro in this file.

[giordano]

There was supposed to be a trailing newline in this file to avoid the warning. Is that missing now?

Merging #44350 and enabling -Werror in CI would have prevented this 🙂

[giordano]

If there are no objections, I'm going to merge this PR on Tuesday