Log Message:
textproc/hgrep: update to 0.3.5

 - Add HGREP_DEFAULT_OPTS environment variable to set the default command line
   options. For example, the following configuration enables ayu-dark theme and
   background colors by default. See the document for more details.

   export HGREP_DEFAULT_OPTS='--theme ayu-dark --background'

 - Detect the terminal color support from TERM environment variable in addition
   to COLORTERM environment variable. For example, xterm-256color enables 256
   colors support. See the document to know the logic of the color support
   detection.
 - Update the themes bundle to the latest.
 - Update cargo dependencies including syntect v5.2.