Fix the errors/warnings reported by PHP_CodeSniffer

Let's correct all the PHP_CodeSniffer warnings/errors, instead of focusing on CSS files.

Fixed most of the issues.

Remaining Issues:

FILE: /home/system/Documents/contribution/nature_blog-3304297/includes/flexslider/changelog.txt
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FOUND 0 ERRORS AND 1 WARNING AFFECTING 1 LINE
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 13 | WARNING | Line exceeds 80 characters; contains 103 characters
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FILE: /home/system/Documents/contribution/nature_blog-3304297/includes/flexslider/node_modules/jquery/CONTRIBUTING.md
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FOUND 0 ERRORS AND 16 WARNINGS AFFECTING 16 LINES
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  13 | WARNING | Line exceeds 80 characters; contains 250 characters
  27 | WARNING | Line exceeds 80 characters; contains 177 characters
  38 | WARNING | Line exceeds 80 characters; contains 358 characters
  45 | WARNING | Line exceeds 80 characters; contains 229 characters
  54 | WARNING | Line exceeds 80 characters; contains 168 characters
  69 | WARNING | Line exceeds 80 characters; contains 207 characters
  71 | WARNING | Line exceeds 80 characters; contains 99 characters
  79 | WARNING | Line exceeds 80 characters; contains 167 characters
 112 | WARNING | Line exceeds 80 characters; contains 102 characters
 124 | WARNING | Line exceeds 80 characters; contains 112 characters
 131 | WARNING | Line exceeds 80 characters; contains 95 characters
 155 | WARNING | Line exceeds 80 characters; contains 236 characters
 181 | WARNING | Line exceeds 80 characters; contains 103 characters
 199 | WARNING | Line exceeds 80 characters; contains 352 characters
 205 | WARNING | Line exceeds 80 characters; contains 107 characters
 214 | WARNING | Line exceeds 80 characters; contains 109 characters
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FILE: /home/system/Documents/contribution/nature_blog-3304297/includes/flexslider/node_modules/jquery/README.md
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FOUND 0 ERRORS AND 38 WARNINGS AFFECTING 38 LINES
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   7 | WARNING | Line exceeds 80 characters; contains 235 characters
  18 | WARNING | Line exceeds 80 characters; contains 148 characters
  24 | WARNING | Line exceeds 80 characters; contains 83 characters
  32 | WARNING | Line exceeds 80 characters; contains 110 characters
  49 | WARNING | Line exceeds 80 characters; contains 122 characters
  61 | WARNING | Line exceeds 80 characters; contains 136 characters
  74 | WARNING | Line exceeds 80 characters; contains 112 characters
  75 | WARNING | Line exceeds 80 characters; contains 165 characters
  77 | WARNING | Line exceeds 80 characters; contains 156 characters
  81 | WARNING | Line exceeds 80 characters; contains 160 characters
  84 | WARNING | Line exceeds 80 characters; contains 86 characters
  85 | WARNING | Line exceeds 80 characters; contains 189 characters
  86 | WARNING | Line exceeds 80 characters; contains 100 characters
  87 | WARNING | Line exceeds 80 characters; contains 101 characters
  88 | WARNING | Line exceeds 80 characters; contains 98 characters
  89 | WARNING | Line exceeds 80 characters; contains 102 characters
  90 | WARNING | Line exceeds 80 characters; contains 95 characters
  91 | WARNING | Line exceeds 80 characters; contains 109 characters
  92 | WARNING | Line exceeds 80 characters; contains 81 characters
  93 | WARNING | Line exceeds 80 characters; contains 286 characters
  94 | WARNING | Line exceeds 80 characters; contains 361 characters
  95 | WARNING | Line exceeds 80 characters; contains 101 characters
 100 | WARNING | Line exceeds 80 characters; contains 84 characters
 104 | WARNING | Line exceeds 80 characters; contains 251 characters
 118 | WARNING | Line exceeds 80 characters; contains 83 characters
 130 | WARNING | Line exceeds 80 characters; contains 92 characters
 138 | WARNING | Line exceeds 80 characters; contains 92 characters
 168 | WARNING | Line exceeds 80 characters; contains 253 characters
 193 | WARNING | Line exceeds 80 characters; contains 141 characters
 209 | WARNING | Line exceeds 80 characters; contains 104 characters
 213 | WARNING | Line exceeds 80 characters; contains 166 characters
 222 | WARNING | Line exceeds 80 characters; contains 205 characters
 231 | WARNING | Line exceeds 80 characters; contains 121 characters
 232 | WARNING | Line exceeds 80 characters; contains 91 characters
 257 | WARNING | Line exceeds 80 characters; contains 180 characters
 339 | WARNING | Line exceeds 80 characters; contains 85 characters
 340 | WARNING | Line exceeds 80 characters; contains 86 characters
 355 | WARNING | Line exceeds 80 characters; contains 85 characters
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FILE: /home/system/Documents/contribution/nature_blog-3304297/nature.theme
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FOUND 7 ERRORS AND 6 WARNINGS AFFECTING 7 LINES
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   3 | ERROR   | Missing short description in doc comment
  72 | WARNING | Hook implementations should not duplicate @param documentation
  72 | ERROR   | Missing parameter type
  74 | WARNING | Hook implementations should not duplicate @param documentation
  74 | ERROR   | Missing parameter type
  98 | WARNING | Translatable strings must not begin or end with white spaces, use placeholders with t() for variables
  98 | ERROR   | Concatenating translatable strings is not allowed, use placeholders instead and only one string literal
 104 | WARNING | Translatable strings must not begin or end with white spaces, use placeholders with t() for variables
 104 | ERROR   | Concatenating translatable strings is not allowed, use placeholders instead and only one string literal
 109 | WARNING | Translatable strings must not begin or end with white spaces, use placeholders with t() for variables
 109 | ERROR   | Concatenating translatable strings is not allowed, use placeholders instead and only one string literal
 116 | WARNING | Translatable strings must not begin or end with white spaces, use placeholders with t() for variables
 116 | ERROR   | Concatenating translatable strings is not allowed, use placeholders instead and only one string literal
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Time: 47ms; Memory: 8MB