Fix some references and docstrings. (#55)

Author: fredrikekre

src/activefiltered.jl

@@ -17,7 +17,7 @@ The `filter` should be a function that returns a boolean.
 `true` if the message should be logged and `false` if not.
 As input it will be given a named tuple with the following fields:
 `(level, message, _module, group, id, file, line, kwargs)`
-See `?LoggingExtra.handle_message_args` for more information on what each is.
+See [`LoggingExtras.handle_message_args`](@ref) for more information on what each is.
 """
 struct ActiveFilteredLogger{T <: AbstractLogger, F} <: AbstractLogger
     filter::F

src/datetime_rotation.jl

@@ -1,6 +1,6 @@
 using Dates
 
-raw"""
+@doc raw"""
     DatetimeRotatingFileLogger(dir, file_pattern; always_flush=true, rotation_callback=identity)
     DatetimeRotatingFileLogger(f::Function, dir, file_pattern; always_flush=true, rotation_callback=identity)
 
@@ -17,7 +17,7 @@ It is possible to pass a formatter function as the first argument to control the
 The formatting function should be of the form `f(io::IOContext, log_args::NamedTuple)`
 where `log_args` has the following fields:
 `(level, message, _module, group, id, file, line, kwargs)`.
-See `?LoggingExtra.handle_message_args` for more information about what each field represents.
+See [`LoggingExtras.handle_message_args`](@ref) for more information about what each field represents.
 
 It is also possible to pass `rotation_callback::Function` as a keyword argument. This function
 will be called every time a file rotation is happening. The function should accept one

src/earlyfiltered.jl

@@ -13,7 +13,7 @@ The `filter` should be a function that returns a boolean.
 `true` if the message should be logged and `false` if not.
 As input it will be given a named tuple with the following fields:
 `(level, _module, group, id)`
-See `?LoggingExtra.shouldlog_args` for more information on what each is.
+See [`LoggingExtras.shouldlog_args`](@ref) for more information on what each is.
 """
 struct EarlyFilteredLogger{T <: AbstractLogger, F} <: AbstractLogger
     filter::F

src/formatlogger.jl

@@ -12,7 +12,7 @@ Logger sink that formats the message and finally writes to `io`.
 The formatting function should be of the form `f(io::IOContext, log_args::NamedTuple)`
 where `log_args` has the following fields:
 `(level, message, _module, group, id, file, line, kwargs)`.
-See `?LoggingExtra.handle_message_args` for more information on what field is.
+See [`LoggingExtras.handle_message_args`](@ref) for more information on what field is.
 
 # Examples
 ```julia-repl

src/transformer.jl

@@ -9,7 +9,7 @@ to conditionally change the log level of logs from a given module
 The transforming function `f` is given a named tuple with the fields:
 `(level, message, _module, group, id, file, line, kwargs)`
 and should return the same.
-See `?LoggingExtra.handle_message_args` for more information on what each is.
+See [`LoggingExtras.handle_message_args`](@ref) for more information on what each is.
 """
 struct TransformerLogger{T<:AbstractLogger, F} <: AbstractLogger
     transform::F