Some packages are widely spread, but were never standardized by IEEE. Different vendors have shipped different versions, with incompatible implementation. These packages should not be used and are flagged as Deprecated IEEE packages.

use ieee.std_logic_arith.all
use ieee.std_logic_signed.all
use ieee.std_logic_unsigned.all

Instead, use the standard ieee.numeric_std package.

use ieee.numeric_std.all

The package ieee.std_logic_misc has the same problem of not being standardized by IEEE. Contrary to the packages above, there is no consensus on how to replace this package.
Sigasi Studio flags this package as Non-standard package.

Read more on IEEE packages in Deprecated IEEE Libraries.

Project specific setting of this rule

This rule can be disabled for your project, or its severity can be modified in the project linting settings.

Manual configuration in ${project location}/.settings/com.sigasi.hdt.vhdl.linting.prefs:

8/severity/<project>=IGNORE
37/severity/<project>=IGNORE