Fix surround substring to surround all substrings

[mrjsj]

Proposed changes

Fixes #209

Types of changes

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• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update (if none of the other choices apply)

Further comments

I changed the input.find-method to simply use input.replace in order to replace all occurrences of the keyword. It will also replace substrings inside words, which I'm not sure is intentional (see 3rd unit test). Should the substring only be surrounded if there are no alphabetical characters, or maybe no alphanumerical characters around it? I.e.

• Current case:
  • rdd in spark rdd stuff would be surrounded: spark **rdd|| stuff
  • rdd in spark rddrdd stuff would be surrounded: spark **rdd||**rdd|| stuff
  • rdd in spark rdd123 stuff would be surrounded: spark **rdd||123 stuff
• Alphabetical excluded:
  • rdd in spark rdd stuff would be surrounded: spark **rdd|| stuff
  • rdd in spark rddrdd stuff would not be surrounded: spark rdd stuff
  • rdd in spark rdd123 stuff would be surrounded: spark **rdd||123 stuff
• Alphanumerical excluded:
  • rdd in spark rdd stuff would be surrounded: spark **rdd|| stuff
  • rdd in spark rddrdd stuff would not be surrounded: spark rddrdd stuff
  • rdd in spark rdd123 stuff would not be surrounded: spark rdd123 stuff

[SemyonSinchenko]

LGTM

[MrPowers]

Thanks, looks great!